I rather point out some more expensive pins that might not be 4k and under but still deserve to be recognized bc of their current value and potential to significantly increase in price going forward.
Here are my picks
Hobbit- I struggle to find a pin with more going for it at a price that is under 7k than Hobbit. The code, the detail in the pf, the lighting and sound, the shot layout, the monitor, the amazing powder, the EXTRA PF monitor, it has a ton. I currently own one and whenever I think about selling I realize how much I'm giving up. I believe this one will rise soon.
AFMLE - the top rated pinball game in the world (or close 2nd - depending on the day) you're getting the opportunity to play it basically brand new and with exclusive extras including the sickest topper out there. Current price is around 7500-8k which couldn't even touch an updated original before the rerelease. The fact the entire table is a limited quantity - I just can't see how this doesn't go up a lot now that they are all sold out.
Walking Dead pro. I've seen them for sub 5 modded. I still have trouble appreciating it but I know it will click one day. The vault edition of released could impact this but for now amazing value.