cleaner shrimp

My trusted lfs sells his cleaner shrimp for 30 bucks, and my other lfs that i do not do business with (at least fish anyways) sells his shrimp for 20 bucks, im tempted to buy it for the 20 but when hes done me wrong in the past with buying clownfish and his water is just gross and he always has dead fish in his tanks, but his cleaner shrimp are a good price, i just need to know will the cleaner shrimp carry any parasites if i buy it from him? i heard inverts, shrimps don't carry anything that could be harmful to fish? So i guess im asking either pay 30 or 20 for the shrimp?