I make those 504 loans in CA, Nevada and Arizona. You are correct that it would be 10% or 15% down and it will also be lower interest than would a conventional bank loan if you could find one. One thing about the 504 though, is that it is not for startups... although startups are eligible. Generally for a startup to qualify you would need more down and possibly need to pledge assets like a home as collateral. The SBA 504 can also be used for equipment loans. The size of the total project financed can be $10 million or more. However, the most important thing is a really good plan with well done financial projections and assumptions. Look up "Certified Development Company" in your area and talk to a CDC loan officer to help you out.
There is another SBA project called the 7a that banks participate in. These can provide real estate loans, equipment loans, working capital. Lastly, there is the Community Advantage loan. CDCs provide those and they can go as high as $250k. That product is a good one to consider for equipment financing. You would probably need to put down 20-25% if unsecured, but the terms would be much better than using 10-20 credit cards.
The bottom line is that there is financial help out there if you have your act together.