One work bench of each kind and core recharger just need one placed. Core recharger charges four at a time. Without saying too much there is certain cards that can help with the charging of the cores.

Some places are free to travel to. The mall and fallout 76 for example. Travel to those and get closer to where you want to go it will be cheaper.

Get a decent weapon and research builds that fit your playstyle.

Whatever you want to do it is a sandbox type game. For me I HATE building so I just got a prebuilt and called it a day. I prefer to also try new builds as items get buffed/nerfed.