Does turning on my personal hotspot cost money?

I have an iPhone 6 and my service is with metro pcs. I have unlimited 4g data. Would it cost money to turn it on?

There's no reason why it should unless its in your contract. If you allowed them to take advantage of you and not deliver on exactly what they said they would then youve been taken just like all the other shady cell phone providers.

Depends on your provider's T&Cs. I know some companies are more likely to charge its consumers for enabling tethering services, and that's just for enabling it with no usage fro the other devices yet.

From the MetroPCS website.

***Mobile Hotspot
***Unlimited tethering with first 6GB of tethering at up to 4G LTE speeds***

Requires capable device. Certain restrictions apply. For data capped plans, full available speeds apply to monthly data allotment, then speeds slowed for remainder of payment cycle. For unlimited smartphone LTE data plan, full available speeds apply to 6GB of hotspot data per payment cycle, then speeds slowed for remainder of payment cycle.***

So yes it will cost you. You will first have to get the highest plan they offer, and if you are using your Hotspot for streaming movies, games on your PS4, computers, tablets etc, and eat up your 6GB allowance of high speed data, in say 2 weeks, you are stuck at 2G the rest of your billing period.

So while you won't pay more money, to turn it on and use for your other devices, you can burn through it faster than your expect, and have to deal with the slower speed after you do. Which can be pretty slow for most streaming purposes (at least for HD video).

Is this spam?

Is this spam?