Learn English – correct preposition to use with ‘support’ in this sentence

The product may be purchased in U.S. dollars.

In my opinion ... when you say this, the implication is the seller accepts currencies other than U.S. dollars, and there may be a possibility the seller would convert the currency for you - i.e. the sentence is short for "The product may be purchased in an amount of U.S. dollars."

The product may be purchased for U.S. dollars.

Doesn't make sense. Purchasing means you get something in exchange for money, it doesn't make sense to get money in exchange for something (that's selling, not purchasing).

The product may be purchased with U.S. dollars.

This would be the typical way to say this. The implication is that the seller requires you to have U.S. dollars, otherwise he/she won't sell it.

The product may be purchased by U.S. dollars.

Doesn't make sense. It sounds like you are saying the U.S. dollars themselves are doing the purchasing.

Where're you going for your holiday(s)?

Where're you going on vacation/holiday?

You normally use the preposition "on", but the use of the "for" isn't ungrammatical.

As for the sentence "Tell me a good place to go on holiday", there's nothing with it grammatically.