I know i install truffle globally sometimes,
If you switch between projects a lot it might be better to install locally, per project, and then access with ./node_modules/.bin/truffle. That can help when you have to climb into the old time-machine to work on something created way back.
where is that solidity version coming from
First, I am not an expert on this and you can very well see me as a beginner.
This upfront cost is gas price * gas you are sending which is set in your config. This does not necessarily match the real cost. What is important is how much gas your deployment will cost. The rest of the gas sent will not be used.
In your case, you are willing to pay: ...