Bob,
Extremely high quality Firestone Pond Guard 45ml liner can be found on the internet for around .40/sq. ft. If you've got a couple of friends you should be able to lay it yourself in a pond that size. If you have questions regarding seaming or edging I can get that to you.
Using a liner may create some interesting water chemistry concerns but with research you can probably overcome these problems.
This may not be your best option, but I'd hold off on spending the $1 per foot if you're going that route.
