Hopefully... this is in the right section... right?
Just wanted your input on how to you would advertise a webcomic, manga, strip etc without paying money for ads.
I would assume you could try some link exchanges with other web comics?
Get yourself on the major listing sites. At the very least, that means The Belfry (http://www.belfry.com/comics), Onlinecomics.net (http://www.onlinecomics.net/) and The Webcomic List (http://www.thewebcomiclist.com/), though there are many others including some that others will argue are more essential.
Get on a topsitelist. Get on two or three. I don't like them much but they may work for you.
Blog about your comic on Comixpedia. Blog about your comic on Livejournal. Post your comic on relevant Livejournal communities.
Take part in comics communities. Only participate in those where you feel genuinely at home, but do participate in them.
Take part in communities for the interests that show up in your comic.
Take part in a crossover. Do fan art.
And always wear sunscreen. The benefits of sunscreen have been proved by science.
Keep in mind that advertising a comic is a lot like advertising a lot of other things online. Treat it accordingly and start reading some blogs. Not just the ones on comics, but about running businesses, marketing, blogging (yes, there are lots of blogs on blogging -- go figure, but they're damn useful), and anything else that's associated with whatever it is you're doing. There's plenty online about running a business, and like it or not, you should treat your comic like one.
I'm trying to run my own blog (http://lastresort.xepher.net/blog) on the stuff, which admittedly is just another method of trying to advertise the comic and attract readers. That said, it still works, the information there is still useful, and you can update the blog a lot faster than you can your comic.
Find comics you already read that're similar to yours, and start making yourself known in those groups. Don't mess with DeviantArt and FurAffinity's communities (but feel free to post stuff there and try to get more exposure); they're too large, too broad, and you'll just get frustrated if you pay too much attention. Same caution applies to certain LiveJournal groups. At least with comic communities you'll have a far less jaded/dramatic crowd, and they're already receptive to the general idea of webcomics as well.
And check out Project Wonderful for later. Is interesting stuff.
getting involved... and I mean INVOLVED with populated, active message boards with a modest amount of people of either similar topic or theme or idea of your comic, or just comics or webcomics in general, is ALWAYS good. Just put it in your sig and stay active in various discussions. Avoid needlessly brining up your comic/project if there really is no need for it.... it gets annoying because it sounds like SPAM... However, sometimes it's just applicable, and when you do, don't say too much about it.
I dunno.. just use best judgement.
Basically if you can get "in" with a community, chances are good they will be checking you out, and if they like you (not neccessarily your comic) they may even give you a nod on their site.
granted this is a longer way to go about it... it's more of an investment of the project as a whole and on getting more involved in the community... respect and such.
*shrugs* at least that's how I've been doing things, and it has not been bad in any way.