Right now, Costco has Disney swim wear for sale. For Boys, they have the trunks with matching Rash guards for $19.99 (maybe not as cheap as some other places but hey, they're really cute!). For the boys, they have Nemo, POTC, Cars...I think there was at least one other boy themed one. I can't remember what they were selling for girls (sorry!) I just wasn't focused on that since I don't have a dd. The rash guards say they are spf 30 as well. Just thought I'd pass it along.
To answer the OP's question, my ds doesn't have a problem with the material. But he doesn't seem to have particularly sensitive skin either. I hope you find something that works for you!