Are you asking if it's a good price? That I'm not sure of: I work with lavender albinos & pieds. $450 would be on the high side for two 100% het pied girls from this season, unless they had some really hefty size on them already. But clowns are a little pricier than pieds. So I'm thinking it's an okay price.
If you want to work with recessive genes, then yeah, het females are always a good investment. But the big question is, who is the breeder? Do they have a good reputation, is it someone you trust? 100% hets aren't as dicey as possible hets, but people still do pass off normals as 100% guaranteed. So make sure the breeder has a good reputation before you drop the money.