Used Galaxy S3 for Cricket Wireless?

[anon(5992477)]

I need some advice on getting a Galaxy S3 for Cricket Wireless. This is a gift for a family member and I would like to avoid the current price of $479 directly on their site. I don't deal with CDMA phones so I'm unsure if I could find the proper phone on ebay. It seems there are very few available compared to unlocked GSM phones. What do I look for? I think they use Sprints towers so could I buy a used Sprint Galaxy S3 to use on Cricket? Thank you in advance for any advice.