Money is tight in our family too. We are saving our pennies for the IQ testing, but do plan to submit a portfolio in place of achievement testing. He's 8 and whizzing through high school algebra, so I'm hoping samples of his work will be an acceptable alternative to achievement testing.
For the IQ testing, I called dozens of places and finally found one that is somewhat in our price range-- $300. This is a woman who runs an after-school tutoring program for kids with learning disabilities. I know this isn't as good as a tester who specializes in gifted kids, but there is no way we can afford that!
This tester is allowing us to put the testing on "lay-away". I've been tightening our food budget the last few months and paying her $50/month. I look forward to actually having him tested!