Abacuses come in different sizes, formats and designs which determine their costs. There is a wide range of prices due to these particularities, in addition to the brands, which are also often a determining factor in the price.
For your reference, the simplest and most functional abacuses start at 100 MXN and go up to 2000 MXN, although there are many intermediate options of excellent quality. It all depends on the product you are looking for.
The materials also influence the price, as there are abacuses made of strong and resistant wood and there are plastic abacuses more prone to break or split. That's why you should evaluate, according to your budget, how much you are willing to spend and, based on that, look for the best products in that price range.