I don't have any spiders, so can't post pics of them. But...I do like a nice high-white spider...and I love the reduced pattern ones with little-to-no spots. That's just my personal preference.
As for the payment plans...Using checks is a good way to start because then your bank will be able to hold onto that proof for you should you need it in the future. Make a note on the "note" line that it's a payment for a specific snake and what the balance owed still is as of that check. On the last check, mark on the note line "paid in full". AND AND AND make sure you get a signed receipt for all monies that change hands.
Even if someone isn't out to rip anyone off, misunderstandings CAN occur where one party feels they have paid X amount and the other party thinks it is different. The steps listed above, as well as a pre-written "contract" that states exactly how much money is to be spent and over how much time, will help prevent that.
Good luck with it!