well whats your price range?? because if its on the les $ side of morphs i would say a pastel ranging anywhere from 125-250 .. the better pastels being more in the 200 range.. ummm mabye a spider but those are normaly at or over 300...
but if you don't mind spending more money on one i would say go with a BUMBLE BEE (SPIDER + PASTEL). those are anywhere from 700-1,000..
and if you wanted something that holds its color as it gets older... then get a killer bee.. (super pastel + spider).. but those range from 2,000 - 3,000 or a super pastel (pastel _ pastel) those being anywhere from 600-800 .. so there are some ideas for you!!!
as for where you should you get them.. go to google and type in ball python breeders.. a lot of good name breeders should come up.. i got my 1st morph (lemon pastel female) from www.jdconstriction.com and i love her!!! she is very healthy and has very good bright yellow and a lot of blushing!!!!