Depth is not really an issue when discussing mask, remember the only issue would be differential pressure between the water and the air inside the mask and that is never going to get high. If it does, the pain will make you equalize the space. An inexpensive mask will likely not last as long but even then the life is likely many years. The biggest issue I see is most of those mask...or at least the ones we see in the states, they are packaged in a way that you have to distroy the package to get to the mask so trying it on for fit before buying it is pretty much impossible.
Fins are another matter, the quality of mass marketed snorkle fins is pretty bad and while you can use them , they are not a good idea because they do not work that well.
An alternative to inexpensive new equipment is to find some quality used gear. Dive fins from the past are usually still quite good, they may need to have the strap replaced but that is a minor cost. Snorkles are pretty much impossible to wear out and a quality dive mask will last many many years. Try looking in your local for sale adds for used scuba gear, odds are you can find some at a very good price.