I’ve lived in Prague for some time, and believe me it’s damn cheap place, in fact you can go to stag parties and pick up girls easily if you have a room and a car/cab in the early morning after getting totally wasted. And you must go to Karlovy Lazne, you won’t find locals there, mostly foreigners like you and me, but yeah, lot of girls, nearly all single…. and all driven by evolutionary instincts for some crazy shit experience in eastern European nightclub, my blessings with you guys

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As for prostitutes, it’s better to call them at your place.. don’t trust their setting, I’ve burned my fingers.. ouch!!.
But pussy is pretty cheap there, in 100 Euros per hour you’ll get pretty solid chick, but if you are a low budgeted traveler you can try some Russian shit, for that you’ll have to go outside the city and you’ll find Russian brothels there, depending on your negotiation skills (what about applying theory to practice, numi

).. you can get a quick fix there as cheap as 10 euro per shot, but they are not very good in terms of quality control, so take caution.
But if you want to do it for FREE, you can try going to Big Sisters, awesome setting and some of the “inmates” there are pretty hot, but you’ll have to sign a contract that your intimate experience will go live on their site.
And if you have taste for road side stuff, try strolling around wenceslas square in night, there are some Cabaret shops near to that area, you might wanna try out those too.
And if you want orgies, you’ll have to go far out of city, that’s one thing you can’t get there.
But, all in all, Prague is stunningly beautiful and awesome city in every sense, have a bang!