Yep, like Ylva said. Start with who will deliver to you. It is amazing how important that becomes as your business grows.
Not always, but sometimes timely delivery is more important than price. And generally, doing most of your business with one supplier makes you an important customer faster. But it is also good to establish relationships with 1-2 others. More than that can get time-consuming to manage.
I buy most supplies, glazing, & moulding from a distributor that delivers. I buy some moulding, though lately mostly chops and other small things that can be shipped inexpensively from a couple of others. I try to do business with companies that support framers, so 888 is a good choice for hardware.
And it is worth finding someone who can ship you reliably great quality chops. It can allow you to offer higher-end frames right away without the expense of maintaining inventory.
Some folks are really good a managing inventory, but it can grow exponentially and eat up all your space and spare cash if you aren't vigilant!
I was lucky to find a mentor early in the process. You probably won't find one in your home town, but an hour or so away you might find someone to be a big help. If you have the time, make some trips and visit some shops. You will know right away when you find the right one. You will be welcomed even if they are busy!
Good luck. There are a lot of fine framers that will help you along the way.