As someone new to the world of pinballs, you'll undergo a bit of a learning curve. Its doubtful you'll actually be able to analyze correctly the condition of older electromechanical pins and determine there value. Most, but certainly not all, EM machines in good operating condition are only going to bring a resale value of $300 - $500.

Here is a quick lesson. If the backglasses are broken, cracked, have lots of paint flaking or are completely missing, the machine is basically for parts only. Backglasses are rarely available, and if they are, its cost can easily exceed the price of the machine.

A non working EM pinball machine rarely is going to sell for over $200. EM pinballs that have been sitting for a few years almost certainly will not be fully operational. The extent of what it will take to get it fully operational is almost always a question mark.

Condition is of course everything. If the pins have been stored in a shed with a leaky roof, and they all show signs of water damage, they probably are worthless. If mice have taken up residence within the machine, know that mice urine is like an acid, and will destroy metal. Mice also tend to chew up wires, and of course, the smell of mouse poop is not something anyone wants inside there home.

I would recommend buying one of the pins, and getting it operational. Investment is low, and you'll see whats involved in getting it up & running. You might enjoy it. You might loathe it.