As others have said the main thing for a spray booth is it controls overspray and removes much of the muck from the air.
I have two, a proper semi commercial/education rated one in the garage that is awesome for spray cans you almost can't smell the can 30 seconds after using it (graphic air a300 from memory, about £350), and a £100 amazon cheapy one which is much weaker but works well for normal acrylic spray paints inside the house. I would not use the cheap extractor with spray paints at all, it's quite weak compared to the proper one and IIRC about half the extraction area.
I almost always use a P3 half face mask when spraying as long term protection (about £20 for the mark and £15-30 a year on filters depending on when how much you do).
Basically if you do a lot of airbrushing it's definitely worth getting an extractor if you can find room for it, I know people who use modified kitchen extractors (as you can often get them cheap second hand), or build a unit using things like computer fans but the saving vs buying a cheap commerically available one isn't great.
The one thing I would note, is that the cheap ones are hobby models, and may not have the sort of protection that the more expensive models have in regards to sparking etc (not really an issue if you're not using flammable solvents or propellants).
