Clear space in garage

Is there any way to clear space to be able to order a new car if your garage is full?
I know that you can drive a car that you've found into your garage but it's not possible to order one online since it will just say "You have nowhere to store this vehicle."

Now this is a problem, since I accidentally bought some bikes that I thought wouldn't take as much space as a car and now I can't order any new cars since my garage is full?

Is there any way to remove a vehicle and not just replace it with some random street vehicle?

Take a car/bike from your garage to a Los Santos Customs shop. One of the options in the list is sell. Select this option, and the car will no longer be yours, freeing up the space in your garage (and you'll make some cash)!

The only downside is you have to wait a while in between selling cars.

As Timmy Jim says, You could sell it in any 'mod shop' but if you want to keep all your cars, I'd advise you to buy an extra garage, because you will only have this problem again next time you want to buy a vehicle!

If you do a couple of Rockstar's missions(solo or otherwise), you should have enough cash for a cheap garage. It should only take an hour for the average player.

FYI, garages have a set amount of spaces(2, 6 or 10), no matter what the vehicle type (plus bicycle rack).