Hi everyone.... I actually joined this forum to correct the mass of posts being oh so negative about Bulgaria and Sofia in particular.
I lived and worked in Bulgaria so have first hand experience of being there week in, week out in all seasons, and there are plenty of females if you know where to go.
One of the best ways for prostitutes is to drive out of a city on a major road used by trucks, and you'll find them waiting beside the road near a suitable place to pull over and do business.
I can't tell you every place on every road because every now and then the police will clamp down if someone forgot to pay the bribes, so the girls will move to another spot.
There used to be masses around Dobrich due to the large number of roma gypsies there, but as someone correctly pointed out, many have gone west for better money (I do realise this is the Sofia thread), but there were still enough for most tastes a couple of years ago, so not all prostitutes have vanished.
Regarding student areas and language barrier....... guess what, this is 2017 and partly due to the internet 90% of young Bulgarians speak some English, with many of them knowing far more English grammar than we do, so few problems there, as there's always lots of people willing to help foreigners, as it's still part of the culture.
I found a few prostitutes on a main road (central Sofia near Happy and Tsum) from the centre towards the railway station called Maria louisa, but avoid the area after the lion's bridge (Lvov most) after midnight. There was a café on the street during the day, but later at night the owner let girls use the back rooms to take customers. A couple of the cheaper 'hotels' let girls rent rooms by the hour, so again lots of action taking place in the capital city, which is what you'd expect.
One bit of advice which hopefully will not offend anyone - I found in my many years in Bulgaria that many of them have some pride, despite being poor, and also a lot of bitterness at being left behind after the fall of communism, so if some guys come along waving dollars, euros, pounds or whatever and think the cheap Bulgarian 'prossies' will swarm over them........ don't be surprised if they are offended without showing it, and may not give you all the help you expected, and don't be surprised if you don't get laid. That attitude will be seen as arrogance, and Bulgarians can easily take the **** out of foreigners whilst pretending to be friendly.
I found many Bulgarians were really p**** off at foreigners who had read adverts for Russian dating sites and assumed that Bulgarian women were easy and would swoon at their feet.
I know people here are looking for sex workers, but forget Thailand, this is Eastern Europe and different.
If you are polite and friendly, ask waitresses for a good bar or club, and if you're young then no harm in asking the waitress for a coffee within the first day or so to give you time to get to know them. They don't wear padlocked knickers, but there are little formalities to follow so they don't feel cheap......same everywhere really.
If you just want to fly in, find a prostitute and fly out.......... why bother, save your money and pick up a girl from your own country's dating sites - it will be cheaper and no language barrier, also no mafia guy waiting to rob you in some cases.
Lovely country, lots of gorgeous ladies, and lots of people having sex with each other, so just be polite, friendly and careful and it will happen.