Story time: I've been to Thailand and you're not wrong. I was in my early 20's and backpacking around Asia/Europe with a group of friends. When we arrived in Thailand two of my friends were dead set on booking in the hostel ASAP and hitting the local and having as much sex as possible. It doesn't matter how mentally prepared you are- nothing prepares you for Thai prostitutes. It's overwhelming how much there is going on.

First you blowjob bars where it's exactly what you think it is. Lots of comfortable chairs around and men just getting blowjobs while having drinks in complete view of each other. Prices ranged from (I'll use USD prices) $15ish for a public room bj to ~$25 for a closed booth bj (a curtain is drawn around the booth).

Then you have the girls bars where you walk in, have a seat, order a drink and pick out the woman you'd like. The woman comes over and you buy her a drink- once you've purchase the drink and she has a sip you're allowed to touch, flirt and make your decision. If you decide to have sex you pay the bar fine (~$20-30) and that allows you to leave the establishment with the woman. From there you negotiate the sex price which will run you $50-150 depending on if you want 1-2 hours or the entire night and how attractive they are (most will run you $50-60).

Then there was the soapy massage spots. You walk in and women are brought up/lined up and you have a drink and select who you want to be with. These women are the 'top tier prostitutes' and best you can find unless you're willing to spend hundreds of dollars. They'll give you a full body massage followed by sex. This experience will run you $80-120.

Then you have the freelance prostitutes, online escorts, 'whore houses' (the cheapest at around $15 for sex) and so on. You're looking at $15-$80 depending on... well, attractiveness.

We spent 4 nights in Bangkok and all of us were walking funny by the time we left. Not something I'd ever do again, but an experience I don't regret.