On average, listings lease in the $10's per square foot per year. The Lemon Grove region is seeing a a boost in rates. In the last 3 months, the median rate increased $14 per sqft per year.
Compared to the rest of the San Diego market, the Lemon Grove region has lower rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 2 listings have been made available, which means office spaces are probably leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 50% of the listings in the Lemon Grove are subleases, so you might be able to sign a shorter term by taking over a previous lease. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 410 sqft. Most properties in this market are approximately 2 floors. Most buildings in this area were built in 1985 and are Class Class C.