I do custom weapons as a hobby and not as a job (one I probably spend too much time on, but whatever).
My prices and time spent reflect that, you are likely going to find I am not all that expensive in terms of handling your request. But seeing as I typically assemble weapons in my free time, your commission might take a few weeks/months before I get the weapon in game.
If I think there is someone better suited to handling your request and/or helping out with the weapon, I will let you know.
I do not ask for any payment until the weapon is complete, assembled in game, playable, and the whole project is deemed finished by you.

You can contact me at rjc9000 on Discord, whether finding me on the Modworkshop discord or simply messaging me.
Or you can always comment on whatever latest weapon I have made asking for "how do I request a weapon from you" and I'll respond with pretty much the same line as above.

Most of my recent/more famous weapons made typically also involve my partner in crime PlayBONK, who handles the animation side if you want custom animations. Since most custom weapons typically do involve custom animations, then you'll need to factor in PlayBONK's animation rate into your budget, which is separate from my asking price of what I do to set up the weapon in game.