Why don't you set a minimum order amount for placing a bank wire transfer? Small orders can come via Paypal or other registration services. Big orders can come via bank wire transfer.

It sounds like they're actually sending you funds via Wire service. If that's the case, you should probably be using ACH payments instead of Wire payments. The Wire system was developed to be "instantaneous" and to handle very large sums of money (in the 10's of thousands and up). Once it's done... it's done... it happens, NOW. ACH is not as fast and doesn't use the same type of payment network. It was developed to handle much smaller payments.

Wires cost the bank a lot of money. The software costs a lot, the bank has to manually process each one, and they often require 2 employees for extra security. That is why it costs $30 per. With ACH, it's much simpler and doesn't have to be handled manually.

Nearly all businesses can send ACH transactions. It is typically done through business bill pay services. They just need to set you up as a "payee" and then they can easily send you funds whenever necessary.

Without knowing more about your situation, this is about all I can tell you. Hopefully this will give you enough information to start with. If you talk to your banker, I'm sure they can provide you with a solution that meets your needs.

Of course, if you're getting charged $30 per transaction for ACH, you should really find another bank. :-)

You could just charge them for the transfer on your invoice. Say like "If you chose wire transfer, an extra fee of $30.00 will be incurred."

Wow, I am sure you will find other alternatives. Think about PayPal as a good option. Additionally, you might set your price ranges according to your customers' needs and size (big guys can pay a bit more)

If you offer additional attractive services for corporations they will surely pay more money for them.

There are several alternatives to paypal when managing online payments, that have incredibly low fees.

authorize.net

westernunion

moneybookers

usps

A good example for retail money transfers without being required to have a bank account is Western Union. Check out this article on Wikipedia. Hope it could be a good solution for you!

Moneygram is reasonable and easy (using their online service). PayPal and Westernunion are also good.

You should think about your customers' behavior when it comes to getting your services. I mean, why do they buy the cheapest option if they are corporative clients? If they do that it might be possible that you have to make some minor or major changes in the way you offer the service or product.

You might give them a more personalized service (that is actually not much more expensive than the regular one, but they end up getting it because it makes them feel special)

One thing you could do, is just telling your clients the problem you face regarding the extra-price you would need to charge them with if they still want to make the bank transfer. Anyways, that is a tough situation.