can I ask a question of the safe ways to pick a prostitute when traveling into a tourist country ?. for example is it ok to ask the hotel for such things ? if not are there any other places ? concerning the theft or maybe the pimps who ask lot of money or maybe they deceive the tourrists . can I ask something related to that ?
Nothing in our official guidance about permitted topics explicitly excludes questions about prostitution, any more than about any other topic that some might find objectionable, like travel for game hunting, or drug tourism, or visiting Antarctica, or voluntourism. In fact, there is a tag for sex and an old question about shopping Amsterdam's red light district, although it would probably be considered too broad as written if asked today.
Regardless of the topic, the question needs to be phrased in a way that is answerable in the StackExchange question-and-answer format: it should be about a real problem (no hypotheticals), should demonstrate initial attempts at research (i.e. not answerable with a quick search of the web or a guidebook), and should be closed-ended (not answered with an opinion/review or a list).
As you have phrased the question, I would not consider it suitable— not because it is about prostitution per se, but because it is too broad. There is huge variation even within Europe, for example. Regardless of the topic, it is almost always safer on this site to ask about a specific locale.
You also ask about too many aspects at once. It would be better to start with a single, straightforward question, then submit new, separate questions as needed. This gives you the space to establish characteristics of what you consider to be "safe," "inexpensive," etc., and not simply ask for characterizations, which are impossible to answer because there is so much variation from person to person when it comes to standards of cost and hygiene and so on.
Finally, note that "shopping" questions tend to be frowned upon throughout StackExchange, and this site is no exception.