You don't state what types of bugs that you are finding.

Generally speaking, developers are good at testing functional issues - for example, if they are asked to code a "print report" function, they typically will be able to test the "print report" function so that it works as expected. What developers are poor at testing are use-case issues, where you are integrating a function within the larger scope of program. They test to make sure that the "print report" feature works, but not check to see if it handles cases where someone logs out before printing or if someone edits the data right before printing.

You have 3 choices.

1. Hire a separate tester who tests from a use-case perspective.

2. Pay for your contractors by the hour, instead of per-project.

3. Pay for a full-time employee.

As others have mentioned, developers are notoriously bad testers, especially since it sounds like that you are hiring developers for one-off jobs. A lot of development knowledge comes from working and refining the same code. Hiring one-off developers will generate more bugs than having a single person working and re-working the same code.

I've recently been teaching my 12 year old twins how to program with Scratch from MIT.

http://scratch.mit.edu/

It's fun, there's lots of examples, and they seem to really enjoy it.

I see what you are saying about a fraudulent merchant abusing the system, but what is happening now is that the credit card company is abusing the merchants. If I accept a counterfeit $20 bill within a transaction, I'm out $20. The government (to my knowledge) doesn't take extra.

If a merchant processes a transaction that is later found to be fraudulent, why should the merchant be punished if the order was approved by the credit card company? The current situation has led the credit card companies to be lax on security. If credit card fraud cost the credit card companies more money, I strongly suspect that the security problems would be less of an issue. This is what we are seeing now. It's just not a big enough issue for them.

What I don't understand is why the big merchants all don't get together and form a non-profit (or profit) entity to offer a third party card with much better security. If Visa/MC is going to charge high transaction fees and not be responsible for their lack of security, it would be more profitable for the merchants to form their own third party credit card processor.