They are very fast and the least expensive as well for the high quality instruments.
If you need intermediate or beginner level horns call Interstate Music. I also order a lot of accessories from them. They are usually very competitive in prices on beginner or intermediate level horns.
Just two more to add to your vendor list.
Also, I would discuss this with your business office. $300 or more and needing a quote is rather ridiculous. This is a local policy. You may be able to talk them in to any single item over $1500 (or something along those lines) needing quotes. My business office only requires quotes for $5,000 or more per item.