Open it up, make sure nothing looks like it's been on fire. Not common, but that's one of the biggest pains you can have. Most em stuff doesn't go bad like boards or displays in new games can so you don't have to worry as much.

Plastics will probably be the only thing on the playfield you can't replace easily if broken.

I'd try to pay $200-300, I don't think this is a particularly sought after game or anything

I don't know the value, per se, but I'll buy almost any game that is complete and half decent for $250-$300.
Being that it's your first EM machine, the better it looks on the inside would be of more significance to me than the outside, to a point.
Learning about these things on a complete semi running machine is a ton easier than trying to resurrect a basket case. They can overwhelm you quickly. Read up on schematic reading and tune up your soldering skills! Get a decent Volt/Ohm meter too.

That's actually not bad. Pretty standard for any era to be around $100 and many are more.

Not horrible, but if just one of your plastics is destroyed are you going to want to pay $100 for an entire new set?

Look for mangled switches in both the backbox and under the playfield. That caused quite a few headaches on my last purchase. Lucky that there were less than 5 so it wasn’t too bad.

Nope, but that's a standard plastic situation.