OK firstly if you want to buy heels be careful where you buy them, the best ones I have ever had are steps, by dance supplies europe, I highly recommend them, they are more comfortable than most dance shoes and have a heel capable of heel work. You do have to order them online, but I put in an order every year for a big group and so far I have only had one person say they didn’t fit and that’s out of a good 60-100 people. I teach salsa 5 nights a week and they are what I and my dance groups wear.
I recommend you buy jazz shoes for salsa rather than blochs, if buying flats the reason being is that there is more intricate footwork in salsa in general things like cross overs are not as easy in clumpy trainers. Get them split soled with suede bottoms. Blochs are good for more jumpy dances like hip hop or if you require more support in the ankle area.