I need a good order system that's free or very cheap. I've seen ModernBill and ClientExec but I really don't want to spend money on it. Any ideas?

If you want a good order system, you got to pay for it. You can always lease CE if you do not have the budget right now to buy the owned license.

What do you use?

you can try www.whoiscart.net u$s 35 ;)

there are afew:
1-tinytool (i cant give the url since it is my site)
2-http://ispbs.hostplus.net/
3-http://www.solid-state.org/
4-http://www.phpcoin.com/

^^
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