I have been looking to invest and cannot understand the disparity. As of now, bitstamp is selling in the range of 606-608 while coinbase is at 609 and reaching 610.
Disparity?
You understand that the difference between $604 and $610 is less than 1%, right?
The reason they are not exactly equal to each other probably has a lot to do with fees paid for making an exchange, as well as time and costs associated with getting USD into and out of each of the exchanges.
By the way, are you comparing to the price that Coinbase sells their bitcoins to you, or are you talking about the current exchange rate on Coinbase's open market exchange GDAX?
Coinbase will charge a bit more than the current exchange rate so that they can make a profit. Effectively, they'll buy the bitcoins at current market price from GDAX and then sell them to you for just a bit more.