Need advice! Going to Europe and want to use PAYG phone there. Yes? No?

We will be going to Brussels and Amsterdam for 2 weeks in July (from the US). My head is dizzy from all the stuff I've read about PAYG, SIM cards, renting phones, etc.
It seems the best way to go (we don't want to bring our phones) is to get a PAYG phone once we get there, but I have questions - I hope some here can answer them.
What would be the approximate cost for a cheap (not smart) phone there? Would I then buy a SIM card for it? Would a SIM card work in Belgium as well as Netherlands or would I need another SIM? From what I've read, it seems pretty easy to find phone stores that can do this, but I want to know what I'm doing before I get in there so I don't get ripped off.
Also -
My son went to Italy last year and we have an International Roaming SIM card for a blackberry (it was what our service provider - CSpire - provided him for the trip) but we don't have the phone. Would this SIM card be interchangeable, i.e., work in another brand phone (samsung, etc) and would it work where we are going? Would I just need to get a cheap phone?

Sorry for all the questions, but I am tech-challenged and it's difficult for me to try to understand all this and figure out the best for my situation.

Any responses are certainly welcomed!
Thank you very much!

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› See More: Need advice! Going to Europe and want to use PAYG phone there. Yes? No?

I had a lot of similar questions on a recent trip to Europe. I found it cheapest to buy a small pre-paid phone, similar to a Tracphone and add time to it. For keeping in touch with the US, I just used Facebook online, or sent texts through Textem.net. Everyone knew that I was travelling, and so it wasn't that much of a problem. I also have Skype, and could make free face-to-face calls through my computer.

It is probably cheapest to purchase a phone there, but it is probably easiest to purchase a unlocked global phone with a global SIM card that can be used in many countries. That way you know you have a phone and SIM card that will work. If you're looking for the cheapest option, it's probably going to a store there and purchasing a prepaid phone.