I was very interested in ordering a bike online that my friend has in a 52. However I am not quit sure on the size to get. I am 6 foot 1.5 inches tall. I have a inseam of 34.5 inches. I know going to a shop would be the best way but every shop I have gone to has told me different things. Any help would be awesome.

First bike sizes vary depending of the manufacturer. Some measure seat tubes center of bottom bracket to center of top tube (c-c), other measure center of bb to top of top tube (c-t), and yet others measure from center of bb to top of seat tube (c-t as well). So a 57 would be a 58 or 59 with another brand, or even a 60-61.
The best is to go to one of the following websites, enter your measurements, and start from what they advise you.

https://www.competitivecyclist.com/za...LCULATOR_INTRO
https://www.wrenchscience.com/Store.aspx?stylecode=R