I really need to improve my resume. However, I feel that if I spent $200 or $300 on my resume, it would not increase my job chances nor salary significantly, an

I really need to improve my resume. However, I feel that if I spent $200 or $300 on my resume, it would not increase my job chances nor salary significantly, and at the end, would be a waste of money. If such resume writing services offered a money back guarantee (say, a job making at least x within 6 months), I'd jump on it in a second. Of course, resume writers can't guarantee that, and I am in a position that spending $200 or $300 on something that won't return isn't worth it.