Does anyone know of a few good,cheap barrier pieces?

If retirement isn't a factor, you can't beat George Tarlton or Avalanche. If retirement comes into play, then you have a short time until Pyro gets the axe. Some other good barriers who will be around for a while include Terra (not too cheap, though). And I can't think of anymore.

Rookie Magma. 33 points for barrier and x-men ability. Pretty good deal in my opinion. OR the E Magma with a brotherhood team with inspiring command on magneto so she can barrier twice in a row without pushing when she is next to him.

Magma is great (especially the Vet as it can double as a secondary attacker). Shaman is pretty good, too, especially since two of his other very useful powers (Perplex and Outwit) are free actions. And for PC/Barrier combo, Raven (both Icons and Unleashed) is hard to beat.

After the next wave of Retirement hits at the end of the month, R. Invisible Woman (FF) will be the cheapest option for Barrier availible in Heroclix; however, with only a 4 Range, she isn't terribly effective.

I like Raven, Magma, and Shaman as well--all are very good options for Barrier.

I would throw two others into the mix: LE Victor Fries and Ice/Icemaiden...