OK, I don't dance salsa but my wife has a home business selling low-cost dance shoes so I've some thoughts:
1. If you're a beginner you probably won't notice the difference when you switch from street to salsa. However, after you've been dancing in salsa shoes for awhile if you switch back to street shoes you'll probably say to yourself, "How in the heck was I able to dance in street shoes before!"
2. Salsa shoes are most likely based on comments from teachers and students, e.g. my wife and I dance ballroom standard/latin. In talking to local teachers they tell me a main difference between a latin and a salsa shoe for women the thickness of the base of the heel. While the heights of the heels are the same salsa likes a wider/thicker base because apparently the lady leads sometimes. The thicker base gives more stability for pushing off the floor when leading.
However, if you're a relative beginner a low-cost latin should do fine. Make sure it has a heel box. I've seen some salsa without heel boxes but that is just style over substance.
Some of the teachers here told me they like 3" heels but when I measured their shoes they were 2.5". 2.2"-2.5" would seem a good range for a young person.3" is more common for argentine tango.
Look for sueded soles/heels. We have dance shops here that constantly sell beginner ballroomers "character shoes" (which are OK for stage performers) but are not sueded. We constantly have beginners arriving to our classes only to discover they've bought the wrong shoes at twice the price we sell for.
Tip: When looking at shoes the heel and sole should touch the floor evenly. If the heel touches and the toe is pointing in the air then that is the wrong heel for the shoe.
You should also get a shoe brush and some "Neatsfoot Oil" (or similar). The dust on floors dries out the soles. Every once in a while brush the soles (towards the toe) and rub a bit of oil into the soles with your fingers to keep the leather supple.
Good luck!
OB
