If you shop around you should be able to find 4k-8k. However because of your rigidness in having to stay in DFW then you are at the mercy of the areas economics in which case 8-10 sounds reasonable.

Ideally you are looking at airplane rental of 81 to 99 dollars for a C152/C172 and 35-45 dollars for instruction. Anything more is above the 'averages' and thats how people end up paying 10-15k for their PPL

Good luck with your search and I'll be on the lookout if I see anything.

edit: holy lurker had no idea I never posted here.