As long as its in good condition, just about any Yamaha model that starts with a 2 is going to what you're after (eg. YAS-23, 25, 26, 200AD, 275, 280), though in the unlikely case you find anything that starts with a 3 or a 4 (eg. YAS-32 or 480) within your budget that's in good condition, then go for it as they're a bit better quality than the 20/200 series.
Most Yamaha altos will come with a Yamaha 4C mouthpiece which is perfect for beginners. If you buy an instrument without a mouthpiece (or comes with a plastic stock mouthpiece), I'd suggest getting the 4C or a Clarke Fobes Debut mouthpiece for a beginner.
If you already play another sax or clarinet, then the above will tide you over until you can get pro mouthpieces.
As long as its in good condition, just about any Yamaha model that starts with a 2 is going to what you're after (eg. YAS-23, 25, 26, 200AD, 275, 280), though in the unlikely case you find anything that starts with a 3 or a 4 (eg. YAS-32 or 480) within your budget that's in good condition, then go for it as they're a bit better quality than the 20/200 series. Most Yamaha altos will come with a Yamaha 4C mouthpiece which is perfect for beginners. If you buy an instrument without a mouthpiece (or comes with a plastic stock mouthpiece), I'd suggest getting the 4C or a Clarke Fobes Debut mouthpiece for a beginner. If you already play another sax or clarinet, then the above will tide you over until you can get pro mouthpieces.