FYI, OEM are $85.37 MSRP. I sell Genuine OEM Toyota Parts to TN members for 30% off MSRP plus actual shipping costs plus $1.00- $2.00 for materials, etc. So if you can't find something cheaper, or after market, let me know. At least this way you have the OEM price when you go out price shopping.
But to answer your question, ball joints are steering related, I wouldn't just go cheap, I'd make sure they were dependable. If they fail, disaster could happen.
Good luck, let me know if you need anything, even if it isn't parts related. Im glad to help.