Married or not everyone goes through the same tedium. Quittance (from bureau de finance of which many are dotted around Sousse) increased from memory from 50 to 150 tnd. (bought so many of the blasted things they are all blurring). There are other documents you need but you get an automatic 3 month visa so time to get it sorted...it will test your patience to the limit...Bureau des Estrangers is in Kantoui @
Police Station. They speak little or no English by the way. But your husband can sort this out surely?
If you get stuck I can ask my married friend Rachel if the process differs. People like me (not working) have to prove we can keep ourselves. No lump sums regular forever monthly sums into a Tunisian bank account.
Banks argghhhh like the 1950s and little or no due diligance! Mafia paradise here .. Seriously, seriously .. keep an account back home so you have access to money elsewhere. I can talk you through this more but as you CANNOT move TND out of the country or convert back into sterling you MUST be careful how you handle your financial arrangements. Most banks are poxy here but Biat and Societee General seem reasonable. This is a cash country too. ATM cards rarely work in handhelds ...
At your age you will get bored here. It's not Europe and all the things we take for granted like multi-plex cinemas/shops/decent restaurants and mega sports facities aren't here. Private gyms are expensive compared to wages here. Again hair/beauty compared to what we pay is cheap but not on a single wage unless your guy is a junior doctor or something.
Hope that helps. At least at your age I'm encouraged. The younger Tunisians are keen for their country to progress further (its come a very long way in a short time).and are normally fun and friendly. It's much harder for people my age outside the ex-pat community.
I can also show you the places to go for a good night out - music/dancing etc.