Find a User's SE Reputation

Python 2 (with Requests), 149 Bytes

from requests import*
lambda i,r="reputation":sum(u[r]for u in get("http://api.stackexchange.com/users/"+i+"/associated").json()["items"]if u[r]>101)

I requested the API, converted the API to JSON, then summed the reputation via a generator expression. The generator does remove accounts with less than 101 reputation.

Credit for improving the code: Jonathan Allan.