This MacBook Pro 13 inch is from 2012 and has a street price of about $600 as configured.
RAM Upgrades for 2012 MacBook Pro 13 inch
As far as ram goes for this model you can max out the RAM all the way to 16GB on this model and for current pricing it will set you back about $100 (check price).
Be sure to buy DDR3 1600 Mhz SDRAM SODIMMS and replace the 4GB RAM with the two 8GB sticks that you buy
SSD Drive Upgrades for 2012 MacBook Pro
SSD Drives keep getting cheaper and one would argue that in 2017, this might be a better upgrade than RAM. The 500GB spinner hard drive on this is a good capacity and you could keep it as is, but I suggest a SSD Drive. If you’re okay with 500GB for storage space then you could add a SSD Drive of the same capacity for well under $200.00
Battery Upgrades for 2012 MacBook Pro
The battery will probably be shot on this computer after five years of use so you will want to replace the battery. Unlike some of the other new Models or the MacBook Air this is possible and pretty easy to do. Batteries for the 2012 MacBook Pro are about $40 so for the price it’s probably a good idea (check price)