In at least season one of The Good Wife, it is heavily emphasized that Alicia is returning to work to support her family. Is it ever mentioned how much she earns at Stern, Lockhart & Gardner?
We don't know for sure.
However, we can speculate.
In season 1, she returns to the firm as an associate. The range of possible salaries open to her are dependent on a few things including the size of the firm and her level of experience. However, we can use existing information to guesstimate that she stared in Season 1 on somewhere between $73,000 and $160,000.
Of course, if she came in at a higher level than that, she could be higher on the scale. For example, the average eighth year associate earns between $111,250 and $225,000.
On a separate note, there are quite a few fashion blogs online that admire her range of clothing. They've identified quite a few items from Armani, Michael Kors, Rena Lange and the like, so she's certainly not struggling!