'Pricey' is from making the noun 'price' into an adjective. It's a bit casual-sounding and not considered a good English habit. Here in Australia we usually say 'exxy' (expensive).
'Over the top' means it's exceeded the limit and is an unreasonable price. "Over the top" can also describe someone's excessively dramatic behaviour.
It sounds as though the item was described as 'a bit pricey' and the speaker is actually saying, "It's more than 'a bit pricey', it's so expensive it's ridiculous!"