Some guns, most actually, will depreciate over time. Some don't, and others can fluctuate given interest and availability.

Take the Beretta 682 Gold E Sport. I bought mine for just under 3 grand, new. I traded it some years later for a new rifles, scope, suppressor and accessories. Not sure of the total value but I paid nothing with my shotgun for the trade. So we'll say 2 grand. That model dropped a little in price over the follwoing years and then suddenly they became popular. Could be the performance, the fit, and also the "flop" of the 692 (I think they were no where near as good/nice as the 682) but suddenly prices started to climb and after ten years the price of second hand ones were more than what I got as trade value. Prices have since dropped again, but still in the €1,500 mark or more depending on condition, etc.

Some guns will drop until they hit a "low" and usually hover around a certain price tag. Others will drop until they are worth a fraction of their new price but sometimes they are budget guns that cost little to begin with so the overall drop is not huge.

The above is very general and may not hold true for all makes or models. Also if you go into buying with resale in mind I guarantee you'll always find a reason not to buy.

Excuse me if anything I say you already know but with little information on your history I'll cover some bases and let others deal with the rest.

First thing and the only thing when it comes to buying a gun is fit. If you find something you like, try it out for fit by shouldering the gunand checking for fit, cheek weld, eye alignment, etc. If you find yourself adjusting with each shoulder of the gun, no matter how nice it is, its time to keep looking. I won't say ignore the gun, but make a list based on aesthetics, fit, price and when you're done looking start to narrow down that list by re-trying them until you find the right gun. Sometimes, and this may sound odd, the right gun will pick you and it may be something you were not even looking for (had this with a rifle some years back).

Regardless of your ability/knowledge its always better to have someone with you. A sounding board, a second opinion and more importantly someone that'll point out faults/flaws that your "Rose tinted glasses" may be blinding you to.

A good starting point is online searching. Go to a few dealers, and even some clay ranges. Most will let you shoot, under supervision, so you can try a few models/makes and then decide which suits you.

There are a lot of makes and models out there so take your time because if you buy "wrong" it may cause problems with your shooting and will put you off the sport before you've gotten a chance to really enjoy it.

There are plenty of lads with decades of experience on here so feel free to ask as many questions as you want. You'll get great advice and maybe even a few offers of help.