Open Office is a good choice if you're unwilling to pony up the cash and willing to learn.
If not, well, just make sure you have explored all your options. Do you have any friends that would be willing to sell you a copy of any of the office suites. I bought a copy of Office XP from a friend about a year ago for $25. It's not as flashy as the newer versions, but it's more than enough for what I require.
I also pick up quite a bit of software at flea market type expos in the area. Sometimes you get lucky. I bought a Windows 98 full install CD for $5 and purchased the XP upgrade for $90. I saved a bit of cash.
Deals are out there you just have to scrounge a bit.