This will vary greatly, depending on geographical location, which pharmacy you go to, the dose and frequency of your Rx, etc.
Are you having trouble paying for your prescription? If so, you have several options. One, you can always ask your doc to give you samples when and if he has them. Also, just recently, a generic preparation of Lexapro was released to the market. You could inquire at some of your local pharmacies, see who makes it, if they can get it, and make sure your doc's Rx reflects that the generic option is acceptable.
You can also call the manufacturer of Lexapro (or visit their website) and ask what your options are if you're having trouble paying for it. Most of those companies offer different programs for those patients who are struggling to afford their medication.
Best of luck!
depends where you live--In Australia lexapro only costs $5.40 on consession.