Not everyone is suited or willing to fund a patent with credit cards or bank loans. Some of the possible reasons for either scenario are:

1) An insufficiently high credit score.

2) Carrying too much existing debt.

3) Banks typically will not lend less than $1,000. (i.e.: the amount for a provisional patent)

4) The payments cannot be afforded.

5) Other

For what it's worth, we strongly suggest correcting whatever is keeping your credit score down, and/or repaying existing debt before financing a patent. However, for those who simply cannot or will not wait, there is another way: funding a patent with an investor. Rather than committing yourself to a strict repayment plan, with a bank or credit card with payments due immediately, using an investor can buy you more time and flexibility.

For example, let's say you plan to turn the product you are patenting into a business. You want to mass-produce the invention in order to sell or license it. Great! The only problem is that the process takes time.  

Using an investor gives you more flexibility. Rather than demanding immediate repayment, the investor will understand that commercializing the patent is a gradual process. The deal can be structured in such a way, that the investor provides the initial capital for the patent and recoups his money if and when you license it. Of course, the investor will not be doing this out of the goodness of his heart; he will expect a cut of your future profits. Furthermore, you shouldn't take just anyone's money. You need to be careful about whom you allow to invest in your patent. Here are some guidelines:

1) Borrow a little from someone who has a lot.

In his book, Succeeding, John T. Reed advises businesspeople to 'borrow a little from someone who has a lot." This applies to funding a patent with an investor as well. Think about it: if you need to borrow $3,000, and you borrow it from your Aunt Susan who only has $5,000 to her name, she is going to hassle you non-stop until she is repaid in full. She will not be able to "think long-term" and wait however long it takes for your patent to make money. And if it never makes money, you could be in for serious trouble. Don't put yourself in a situation where a mistake could bankrupt someone. Rather, try to only take investment money from someone who has way more money than you need him/ her to invest. The less money respectively that they lend you; the less they will bother you.

2) Make it crystal clear what the investor's recourse is.

Letting someone invest money in your patent is a business deal. Business deals are inherently risky. For this reason, you and your investor need to be on the same page about what the investor's recourse is, should the patent fail to make money. Some investors will want to know that you'll repay them if that happens. Others will happily shoulder the risk and eat the loss. Either way, you need to establish this before any money changes hands. Do not take money from anyone until you know what they expect of you if the worst-case scenario happens. Obviously, from your standpoint, the ideal investor is one who is okay with having no recourse; one who will eat the loss if your patent is a bust.

3) Don't be too quick to sign away future profits.

Some inventors are so desperate to get the capital they need, that they will sign over rights to future profits to people willing to invest. Don't go overboard with this. If you need $500 for a provisional patent, it's probably smarter to use a credit card or even a payday loan than to give someone 50% of your future profits. Who knows? Maybe your patent won't go anywhere and the investor will have invested that money for 50% of nothing. But you have to consider the flipside- What if it becomes a huge hit? Then the investor sits back and collects 50% of a lot for a measly $500. Therefore, you should try to sign away as low of a percentage of future profits as possible.

4) Only use an investor if you cannot use debt financing.

The great advantage of debt financing (using a bank loan or credit card) is that once you repay the debt and the interest, that's it. The bank or credit card isn't going to claim any future profits whatsoever. For this reason, you should generally only use an investor if you cannot fund the patent using debt. It's more straightforward, less of a hassle, and if you have the discipline to repay what you borrow, is far more advantageous than bringing in a silent partner.

(Perhaps the only time it would be better to use an investor is when the investor contributes something other than money; say, if he/she is a well-connected insider in the industry your patent pertains to. In this case, it may be more advantageous to work with them than use debt financing.)

Keep these four tips in mind and you will eliminate many of the hassles and risks of working with investors. Good luck!