Ok, I agree that the prices of small items will be inflated. In Spain what used to cost 100 pta would have gone to costing €0.60, and it did... but at the earliest opportunity prices tended to go up to €1. Large prices stayed the same, with all necessary rounding done up, obviously.

However, considering that it will take 5, maybe 10 years after accession for Bulgaria to be ready for the Euro, I find backing this

They are too afraid that this accession will have negative consequences on the standard of living.

with the possibility of price-gauging by unscrupulous vendors a little disingenuous. If accession will have a negative impact on the standard of living, it won't be because of the Euro.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman