Yeah, marketing in general sort of sucks, but it's unavoidable and if you've made a great, creative game and you poured yourself into it, for years on end... and then priced it reasonably, then you shouldn't have too much trouble marketing it. You'll find it's easy to promote your game just by default, because you actually genuinely believe it is a worthwhile game that people will like, maybe in some cases even love if they only knew it existed. But the biggest key takeaway in any case is your game must provide great value for buyers. The buyers who buy it will then be far, far more likely to support you as a result. They become your fans.
I'm convinced that indies can punch above their weight marketing their work, even if their budgets are small. The less important keys, after you've made a great game, are:
1) leveraging and growing existing social networks, online and offline, posting your release announcement on FB, Twitter, etc. I also really like Pinterest, as it's inherently visual - so it's a perfect place to post beautiful images of your game's artwork.
2) Signatures in any forums/bulletin boards or online communities you frequent. Just a simple .JPG banner image of your game and its title, with a link tot he game's website or store page, and then just have it there as your default for the bottom edge of your posts. Best if the posts are substantive and the community is a relevant group that might actually be interested in your game. If you have a website for your game, like, an actual one with a nice domain name, then you can make and post those banner signatures on a page there, plus desktop wallpapers, printable poster art, social 'follow us' links, etc. Maybe a few of your connections and followers, fans, what have you, will actually use them and this will go viral. Make it as easy as possible, for your stuff to go viral.
3) Advertising. I hate how expensive it can get but sometimes you can get amazing results by testing out variants of an ad and seeing what works and what doesn't on each platform - or in marketer speak, A/B testing) and then pouring the rest of the budget into whatever form is proving most efficient. I'm kind of thinking Google, FB and Twitter are popular but there is potential in smaller and less obvious ad networks if you know what you are doing. I've had modest success promoting stuff on Quora and Bing, as well as Reddit. Key with the more cynical Reddit though is not to be overly sales-y. You should write simple casual ad copy that includes a pic that encapsulates your game, the name of the game, its most interesting features, etc. I used to get amazing mileage with a few banner ad networks including Project Wonderful, but PW is gone now, too bad. In general know what the terms mean. CPM is 'cost per thousand views' and usually it is about $0.10-$1, more precisely targeted ad networks frequently can cost more in CPM but deliver higher CTR or 'click through rate' - the percentage of people who see the ad and click on it. Typically this is around 1% at best, as people tend to ignore ads, but a great ad can sometimes be fine tuned to 2% or more. Finally, CPC is 'cost per click', meaning the amount spent for each person who actually clicks the ad. But the key at that point is to find the RIGHT audience so they're more likely to respond to the ad no only by clicking but actually *buying* your game, at which point hopefully, if you optimize it all well enough, you wind up with a few ad setups that have a great ROI, or 'return on investment' such that every dollar spent results in multiple dollars worth of sales. I have NEVER had a product with a substantially positive ROI from any of these networks but hopefully with more and better product lines, over time, that will change. Marketing... while the options vary, in general the ad itself and the subset of the audience it displays to, are usually more crucial than the network used.
4) Multiple games, multiple product lines. The more stuff you've got that is actually decent, the more the probability of a visitor finding something they like and actually want to buy. Also make sure your game pages include links to the bigger store and that each game or product includes a little .PDF readme or something, that gives any help needed for players, with controls or whatever, and also identifies the creator of the game and links back to the official site and storefronts.
5) Finally, incentivize retention from past customers and try to keep them in the loop post launch. Email lists or social network follows are great; if people like your first game they are the best chance for immediate sales of your next one. It's not enough to grab sales, try to build a following and while you should not constantly spam people, you SHOULD respond to comments and questions from players and you should post when there's real news relating to what you are doing next. I've seen so many successes fail to repeat because the audience drifted away. Don't be that game developer who was a one hit wonder, and then was ignored in every game after that. Do what you can to build on your momentum instead of allowing it to disperse and dissolve.
Incidentally, here's a small .GIF related to my upcoming game:
http://www.miniaturemultiverse.com
https://matthornb.itch.io <- I also have some stock media collections that are similarly very extensive and like my game have been built up over multiple years of work before any of it wound up on Itch.
I've put well over $1k into MINIATURE MULTIVERSE, and I do realize it's an oddball project - a first-person panoramic interface graphic adventure game with O scale miniature graphics.
It will be launching this summer hopefully... barring surprise delays. Over ten imaginative and varied worlds in handcrafted miniature, 25 major 'areas' and 200+ panoramic nodes. It'll be on Itch.IO and Steam at a standard price of $1.50 and the two versions will launch at roughly the same time. (I intend to submit the Steam version first, then post on Itch shortly after that.)
Think of it as a 'Myst-like' art/narrative game (made in Unity), but with the charm of miniature graphics and far less obtuse puzzle design than the old-school adventure titles, so that I think won't alienate most players. Lots of challenges in designing this but I'm excited to finally see it through.