Yes, there should be very strict limits on how much campaigns can spend. This will benefit the United States as a whole by having the best candidate win an election then the candidate with the most money to spend. With no limits on campaign spending, we will keep getting bad politicians.
Campaign spending has gotten out of hand. We're have presidential candidates getting hundreds of millions of dollars for their campaign. That money could go to much better causes. However, this is not even where the problem lies. Candidates in smaller races are able to gain a distinct advantage if they are able to spend more money on their campaign. One candidate may buy promotional ads, while the other has no other form of publicity but word of mouth. Who do you think the majority of peoples will hear of? The best candidate may not always win when there is no limits on campaign spending.