Marketplace has vendor booths where someone can rez the booth and make a percentage from its sales..

[KikasareHana]

my question is where am I allowed to rez these booths without penalty or disrespecting land owners ? how do i do this ?

[Catwise Yoshikawa]

Not sure what you mean, are you talking about magic boxes to sold your items or just a vendor? For both you will need to rent a land or buy one to be able to rezz your things and start selling ;-)

[Rolig Loon]

You may find a friend who is willing to let you rez a booth or vendor panel in her/his shop, but in general it's a bad idea to try and do it on land that that you don't own or rent. For one thing, rezzed prims count against the land owner's prim allowance, and for another, you are making a profit without paying appropriate rent.  If you are lucky, you will just have your booth returned.  If not, you'll find yourself banned and AR'd.

[Peewee Musytari]

You need to rent or buy some land.

The cheapest way would be a small kiosk style shop in a mall. Check out the various malls where you think the customers would be looking for your product and rent a space in each of the best ones.

You can offer the mall owner a % of sales in lieu of rent of you wish to use the vendor you described.