1. Some of the apartments do have parking space lots. They're just pretty rare. 2. some people have used cheats to put a parking spot indoors and then "pocket" the car permanently as noted above 3. you can also use cheats (and really in this case, it's more of an Advanced Edit unlock!) testingcheatsenabled on RestrictBuyBuildInBuildfings off
you can edit the grounds of the apartment and slap a space on the ground floor. (BTW that cheat may be restrictBuildBuy not BuyBuild, I forget and use the help command to look it up half the time.) Me, I park on the sidewalk. The nice thing about RBBB is that you can go on to edit the public area of the building and add in things like a laundry room or remodel your apartment to expand. There are a few things to keep in mind like don't delete NPC doors and place "public area markers" in new common rooms (visible if you also use buydebug on) so you don't pay tax on them, but it's pretty simple and gives you a lot of designing power.