if i had the money i would find a nice female super pastel first, then add 2 or 3normals about 800g to 1,000g range, then get a nice bumble bee male.
you can always add more females (pastels, spiders, normals, ect.) as you get money.
i didn't have the money so i started with a pastel male last year and added 2 spider females this year.
i wouldn't breed rats until you have atleast 6 or 8 snakes. you work at a pet store so maybe you get a discount on rats anyway.
as pfan151 said buy nice looking snakes not cheap snakes