I've been warned that I'll encounter many people who will try to gauge me.
Guessing you meant 'gouge'?
Best information from you will get the best information from the peanut gallery. Clear pictures. Make, model, markings, barrel length. But mostly pictures. Use a tripod, take lots, choose good ones to post.
Picture posting. You need to load the pictures on a photo hosting site and copy the "IMG" code to paste it in to the post, or you need to pay for a membership here that will allow you to post pictures directly.
I use Photobucket, but snapagogo, and a whole pile of others are out there. Free to use, not too hard to figure out.
Open the picture in a photo editing software, and blur out the serial number if ya feel the paranoid need. Do that before you upload.
So. Whoever told you that folks would try to gouge you. Did they also tell you that the guns were "Worth a lot of money!"? Maybe they were talking out of their rectal end. Picture will tell.
Look around the web for the same make (which is usually marked) and model (which isn't always obvious). Prices are different here than in the US, but you can at least get an idea from the US gun auction sites.
Details matter. Different optional extras in some cases can make or destroy values, depending on whether they were factory/gunsmithed/added by a basement hack with a welder/etc. Thus the reason for clear, well lit, detailed pictures.
So, in the end, it all depends on what it is, and how well you are able to take and present the information. Form your own opinions of the prices suggested, and check and cross check any and all info (including this!

)
Then you will need to decide if you want to price them to get the most money, or for a sale that will happen in the most reasonable period of time.
Take a look in the EE, and watch a section or two that interest you, for a while. You will see a lot of guns that are priced well that sell very quickly, and some that are apparently, going to be buried with their owners, as they are never gonna sell and have been bumped back to top (equals "BTT") several dozen times at the same price. That's your decision to make though.
Cheers
Trev