55-60gallon tank for 6 Goldies and 2 Dojo Loaches. I m wondering what kind of air pump i should get and how many for my 55-60 tank. Please help me out i m new

It depends on your filtration. It may turn out that you don't need an air pump at all (unless you have an undergravel filter). You can check the oxygen level of your tank (tetra has a kit for that) and if it is below 5mg/l you should get a larger filter or add airstones and an airpump. Otherwise, there is no need for an airpump

Single, small air pumps here in Aus. only cost $10-$12 Aussie dollars, so I should imagine they would cost the same in your country. If you are on a tight budget you could try one and perhaps up-grade to a larger one at a later stage.
If you find that you do need a larger one, at least you will have a spare for little monetary outlay.