First Land
Luckily for you, Linden Labs gives you a steal on land right off the bat. It’s called “First Land”, and it’s available for only $1L per sq. m. You pay no tier fees on it, and you can do a number of things with it.

Build On It
512 sq. m isn’t much, but it’s enough to set up a small house or shop. If you want more for your store or lair, check with your neighbors and see if they are selling.

Rent It
The first thing I did when I bought my first land was to create 4 rooms, 400 sq. m each, stacked on top of each other. Then I went out and bought a “Rent Cube”. If you don’t know how to script, search for “Script” under “Find” and look for a shop selling scripts, like “Scripts Unlimited.” All the script shops I visited had one. I set up four rent cubes in each of my rooms, and put them on the market for a market rate of $100L/week. After a couple days, I had all four rented out, and generating an extra $400L/week in income.