1)- Research your purchase. There are several very helpful websites that can save you a lot of money in expensive mistakes: "http://www.saxontheweb.net/vbulletin" is the best saxophone forum on the net. "http://www.saxpics.com/" is an excellent resource for checking makes and models. 1) (a)--Know your brands: Selmer Paris made (and make) professional model horns, Selmer Bundy did (and do) not. Conn, Martin, King and Buescher stopped making professional horns in the 1960s. Yamaha and Keilwerth make student and pro horns (some Vito altos are re-badged Yamahas). Some Rampone & Cazzani/ SML/ Buffet/ Dolnet/ Whatever horns are excellent. Some are rubbish. Yanagisawa makes only pro horns. More recently, some taiwanese horns have gained a good reputation (but not a good resale value). 3) Be careful of horns with dents/ bad scratches/ bits missing/ worn out pads/ no case - unless you know what you are doing. Saxophones are expensive to fix! Every horn I have bought through the internet has required (at least) a service by a trained sax repair-person (thanks Elaine and Brad!). 4) Be aware of shipping costs and taxes! Saxophones are fragile, unless they are packed carefully. They must be supported inside the case. 5) Make sure the instrument is Low-pitch (A=440 Hertz). This applies mainly to instruments up untill the 2nd World War. If the horn is High-Pitch, it cannot play in tune. 6) Make sure that Tenor is a Tenor and not a C-melody (unless you want a C-melody!)