You could buy those APW3++ psu's from Eastshore, I've used them for many times without any issues.

They write a low value for the customs.

Delivery via Fedex is pretty quick to here Finland.

You can calculate your shipping costs to Bulgaria at the website.

-> https://www.eastshore.xyz/shop/power_supply_1600w_bitcoin_miner_use_powerful_bitcoin_mining_psu/