Hi Ryzi, there are Yellowbelly Royals which don't look very different from normals, however if breeding they have the genetics to produce an Ivory. They are around the £150-£200 mark. Pastels are probably next up from about £200 for a male.
Albinos are coming down in price all the time, you can pick them up for ~£500 from a breeder.
I just came across this site so not sure wot they are like... so if anyone has had, or knows anyone that has had any dealings or got any info on them i would like to here it...