Check out eBay for some deals. You can get "new" or barely used premium cranks for about $50-75. I would suggest getting a new bottom brackett as well (due to the age of your bike). If you're replacing the cranks, it would be safe to bet you need a whole new drivetrain as well. (cranks, cassette, chain), this can get expensive all at once, but will probably be the case! Cranks @ $50, bottom brackett @$25, new chain @ $18, new cassette @ $30. adds up to about $123.00 seems like a lot, but cheap considering how much maintenance on a car would cost.
To keep things simple, get some new cranks with the same size (#) chainrings. A 42/32/22 is pretty standard, but there are many variations, so count yours and buy the same!
Of course, you'll have to do the work yourself or pay someone to do it for you. Maybe a cycling friend would do it for a 6-pack and teach you at the same time!
Also, you'll need a couple of special tools to do this including a crank puller, bottom brackett tool and a chain breaker! This is where the friend with tools comes in handy!
Yeah, I know you're not made of money. Me either! I just buy tools as I need them, and learned as I went. Pretty soon, I had a full set of tools and a lot of friends needing help with their repairs. Read, ......a lot of free beer, and good times that go along with the sharing of those beers!
Good luck and if you go the "do it yerself" route let us know and we'll help out any way we can!
L8R
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"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming, "WOW, What a Ride!" - unknown
"Your Bike Sucks" - Sky Yaeger