OK, SBI ... that enlightens us quite a bit. Probably the best thing to do is to drop by the chat some evening, for some more specific advice.
In the meantime .... A small roll-around certainly has it's place. One of the mid-grade Sears Craftsman models, with a molded plastic top and particle board insert should do just fine.
Keep an eye on the size, for two reasons. First, a large one might not fit where it needs to go; second, don't take anything to work that you can't take home on a moments' notice.
Lack of a megger suggest a bottom shelf operation. You're probably going to be working more with parts changers than real problem solvers. You beat them with education.
Contact your community college, and get a few courses under your belt. I'd start with troubleshooting, followed by a controls course. These will help you understand the processes at work.
Get familiar with Harbor Freight, and other such 'cheap import' places. It's not about price here; they're your easiest source for a lot of 'industrial' tools .... pullers, pneumatic ratchets, etc. I expect you'll need them.
Keep an ear open for places where your co-workers have been employed .... and check those places out. Don't let horror stories put you off - check the places out first hand. It's likely some of your co-workers are on their way 'down,' rather than 'up.' Plan on moving to a better job after you have a course or two under your belt ... but be ready for the layoff the first slow-down or management change that comes around.
If the company doesn't actively encourage education, keep your mouth shut. Telling folks you're taking classes will create problems ... trust me on this! If you just happen to find a problem faster - well, the reason why will be our little secret.