I was going to get starter pullets but if I need 50-60 that's a lot of money so its cheaper to buy baby chicks and for the heap lamp I am going to use a heat plate because i don't want to take the risk of a fire
I hope you mean heat plates as you will need quite a few of them to handle that many chicks. Whatever the capacity claim is of the plates you're considering, halve it, and calculate number of plates from there.
With larger groups, a heat lamp (or two) is probably a better choice as it covers a larger area.