Start deciding what you want this horn for. Marching band? You need a good horn that is more robustly built than any other. Jazz? You need one that has that jazz sound etc. etc. It can save a pretty big amount of money in the long run.
Collect your local newspapers and auction lists as well as ebay. Most of them have great deals, you just need to know what to look for. Look for names like selmer, buescher, conn, king, yanagisawa, yamaha and keliwerth. These are good brand names for horns that have good quality about them (be careful with anything else, either.) It’s an expensive antique or b.) It’s a junk of shit that breaks when you touch it. )
Then follow your leads as you came from step 2. Find out the model and serial number for each, do some research on the internet, there are some good sites that list the serial numbers of horns (now if you only get a marching band instrument this step is not so important). For jazz and classical players, this is a special warning, you probably already know the professional models in today’s horns, but some vintage horns are quite different. For example, I personally would never ever play a rooster or buescher for jazz that was done today, both of these companies were bought out in recent decades. BUT the vintage confectionery (with the auto tunnels) is pearls and plays beautifully and the buescher top hats are also good under valued horns.
For march bands I recommend a fine medium hair of almost all companies, selmer bundy s, vito s, buescher 200 s etc. etc. and most can be found relatively cheaply.
Go to the horn if possible. Look at it if you know what you are doing, but if you do not see if the owner lets you take it to a technician in the area to see how much work needs to be done on the horn (this can not be done with ebay so beware). Pads, springs and cork must be checked If you can get away with this I play it myself, I know when you buy new horns you have to play to get a feel for it so see if it’s okay with the owner and keep playing . Look for rust and dents as well, but if the horn plays well, it is only superficial and does not matter if you do not want a nicer horn.
So that s it in addition to one thing, prices. For a marching band instrument or top player $ 500 should be the maximum. Now if you are a proud parent and want to spend more it is good, but be warned, young players have a tendency to tear horns or quit music after just a few years while marchband is a completely different animal that eats horns alive due to bad playing conditions (water is bad for wind gusts). For concert horns, you are looking for a good solid horn that plays well (if you also accidentally run over these horns will give you a look
which Selmer Paris model, Buescher Top Hats, King Zephyr, Yamaha Custom Z, Buffet Dynaction). Jazz horns are good on vintage due to the difference in sound and metals used, but be warned early on, early horns cannot be used with modern tape equipment. the fact that they are actually tuned to a different frequency than today’s instruments, this is just the time (before the 1930s) so be careful with these older horns. Buying a used saxophone can be fun. Good luck with your shopping and hunting, it’s part of the fun!
Tips and warnings
How to buy a used saxophone. Do you want a saxophone? Or someone you know, wants one? The new ones can be expensive but there are sometimes some good deals out there for the older horns, here is a good little guide.