Do you pay for mod/texture packs? If so how much?

In minecraft it is VERY rare for a modpack or texture pack to cost money. Almost all of them can be downloaded for free off of websites. However, if a download tries to make you take surveys or complete an offer, it is not legit. However, the short answer to your question is no. Obviously if it asks you for a credit/debit card number it is going to cost money.

tl;dr: no, most are free.

No, they're free. But you have to find a place that hosts these mods.

No the pc version has free mods and texture packs if they charge money it is a scam and please report them to manjong.