Unless you have your mind made up to buy new, with a little careful shopping you can come up with a combination on your own.
If you decide to go used, the most important fact to remember about Ithaca 37's is that their barrel threads were changed at serial nbr 855,000. Prior to 855,000 the interrupted threads actually had a "pitch" to them, and barrels had to be fitted to the receiver by a gunsmith who understood the dimensional relationship.
After 855,000 they used what were in essence, parallel "V" grooves.
I have seen quite a few nice condition later model (post 855,000) vent rib, choke tubed 12ga guns for sale for less than 400.00 locally and on the web (gunbroker, etc).
If you would buy a used one then you simply could buy a barrel from Ithacagun and come in hundreds less than buying new. I bought a used one a few years back, bought an aftermarket laminate stock and forearm, fitted them on and have a really nice gun. If I didn't have my 2 Deerslayer 2's and needed a rifled barrel, I would simply be able to get one from Ithaca.