You don't need to buy any morph to prove her out, just a normal male/female to breed with. Pastels are codom and will produce roughly 50% pastels, and 50% normals. If you get another pastel you will get (don't quote me) 25% super pastels, 50% pastels, and 25% normals.
Pastels are an affordable morph, that's my first and so far only morph. They are the least expensive at $100-$150 on average. I bought a nerd pastel for a great price and he keeps getting brighter with every shed.