Setting up owner finance

[Eric Giovannucci]

I have a 3bed 3 bath SFR for sale for 140k

15K down 

125k financed @ 8 % 

I will have a previous note for 124k @ 3.5%- Mortgage and Escrow at 

Buyer wants to place cash down as soon as possible, we have a verbal agreement and I have contacted an attorney (www.lonestarlandlaw.com) in the state of Texas to do the contracts (he is charging $750.00) 

Looking for advice as far as being totally protected and if this is a good deal/good choice on attorney?

This is my first owner finance deal and would appreciate any input!