Wife approved a budget this a.m. of up to $2500 for 4th and last pin for awhile. I really only have room for that many anyway. Tried having 5 once but 5th pin was in garage and that doesn't work well at all.
Some pins of interest:
Early classic solid states including Bally, Gottlieb, Stern, Williams or Zaccaria.
Capcom Breakshot or Airborne.
One of the less costly modern Sterns such as WPT.
Might even consider an EM but would really need to be working well especially with the scoring and keeping track of which player and ball is up. I stink at working on EM's, sadly.
So my range is sort of all over the place re: era and manufacturer. Of course, I'd have cash in hand and the plan would be for this pin to stay awhile, not looking to purchase and resale quickly at all.