Nobody’s really sure what the future holds for the UK or for its economy
here’s a quick rundown of how leaving the European Union will affect you
Don't you mean might affect you?
British drivers may need to have their passports stamped at border crossings
Oh noes, not just inspected but actually stamped as well? There are no border crossings within the Schengen area (well, except for all those where EU countries have just re-imposed them due to the migrant crisis) so this will only apply at the entry points like Dover & Calais, where passports are already inspected. Just as they currently may be at the French/Swiss border, the French/Belgian border, etc.
As for finance, British motorists get a pretty good deal already, you'll never find a 0% interest deal in France, for example, because it's not legal under French law, so it clearly isn't EU law driving that. If Germany wants to keep it's biggest European market happy it might even offer better deals to UK drivers over time.
There may also be some positive outcomes. The plan to exchange info on speeding tickets will probably fall, so if you're flashed by a camera on a French autoroute you'll not find yourself getting points on your UK licence.