Hmm, well that depends on what you want to make. If you want to make a BEL, blue eyed lucey then you should look into getting another mojave, butter, lesser, or het russo. If you are looking to make other combos, a pin makes jigsaw, a pastel makes pastave, a spider makes a mojo spider (not sure if they have a different name), and that's all I can think of right now that are low end (less expensive) morphs.
I also really like granite mojaves and sable mojaves. You'll just have to check out all the combos and decide which you like best!