There are thousands of possible interests and hobbies that one can enjoy (check out this list!). If you're reading this, then you've probably already made "chess" on one of your personal interests - and lucky you! Chess is among the cheapest hobby/interests you could have!
Let's compare (prices in USD$):
Astronomy - $100-1000 for a telescope!
Golf - thousands of dollars for golf clubs, then from $25-300+ just to play for a day. hitting a bucket of balls even costs ~$10 for a few hours.
Paintball - hundreds for a paintball marker/gun, and then hundreds for ammo
Video Games - hundreds for a gaming console or good PC + $50+ for a game!!
Comic Books - each one is a few bucks, and they add up fast!
Photography - unless your taking mental pictures only, a good camera costs $$$
Skateboarding - $100+ for a good board, and you tear through shoes too
Almost every hobby I can think of, with the exception of other online casual games, is more expensive than chess! Birdwatching - $100 binoculars; Parkour - medical bills + shoes; Tennis - racquet + shoes + balls... I could go on forever!
To play chess online all you need is a computer and an internet connection, which you already have (or you wouldn't be here reading this...)!!
Now, if you take your chess seriously you might want to spend a little extra for some features or lessons or membership to a really great chess site (cough, cough). Some people say they can't afford, say, $29.95 a year for something that they will probably spend hundreds of hours on this year. :) So I have come up with a list of ideas on how you can, with very little effort, and regardless of your age or economic circumstance, put together a few dollars to more deeply enjoy for your favorite thing in the world => chess.
Suggestion #1 - Compare: Change your paradigm a little and realize how cheap it is when you compare it to other hobbies/interest you might have. Or think about how much money you spend on a night out at the movies, or a dinner, or a case of drinks, or music, or a few books. Comparitively, it's nothing.
Suggestion #2 - Small Sacrifice: Decide how much money you need too put aside, and then make a small sacrifice of something else. Instead of going to a movie or buying the DVD, wait for the rental. Instead of buying the hard cover book, buy the mass market. Instead of buying the $60 video game, get it used or $30.
Suggestion #3 - Quit Bad Habits: Use your cigarette money on chess! Or take another bad habit you have (buying too many soft drinks, etc) and instead set that money aside for a positive thing - chess!
Suggestion #4 - Get a Sponsor: If you are younger, tell your parents or a mentor that you are trying to get better at chess an you need a few bucks - one of them may happily support your endeavor!
Suggestion #5 - Birthday/Holiday Present: Tell people you want a chess membership for your birthday. Then tell them how to get it. It's a much more interesting present to give than another lame gift certificate...
Suggestion #6 - Sell Stuff: See all of those books, CDs, or DVDs sitting on your shelf over there doing nothing? Sell a few on www.half.com or something. That old surfboard hanging in your garage? Put it on www.craigslist.org. Almost EVERYONE has some useless stuff sitting around - sell it on www.ebay.com !
Suggestion #7 - US/World Economic Differences: If you have trouble with the fact that US dollars are expensive for you in your country, consider this: you can take advantage of this by earning US dollars on the internet! Signup on www.rentacoder.com or www.elance.com and sell your skills at a higher price. You don't have to be a programmer - there are lots of other jobs like building links, writing in forums, etc. One other really great option is: http://www.mturk.com/mturk/welcome - where you can get paid small amounts for doing simple tasks like just sorting pictures online!
Suggestion #8 - Chess.com Referrals!: Last but not least, refer friends and chess enthusiasts to Chess.com and you can earn Premium Membership time for free! For each person you refer who becomes a paying premium member, you will get a 30 day extension on your own paid membership (or 30 days silver membership if you are a free member). It's simple to do: either invite friends with this email tool, or Spread the Word with these blog/widget tools!
Chess is a wonderful game/hobby/interest/lifestyle - we're so lucky that it can be enjoyed for so little!
Heading off to sell my golf clubs...