DENVER -- The word "fee" has been tossed around a lot lately.

Cities are increasingly passing or considering raising the amount of money residents pay to use recreation centers, libraries, and trash collection services.

The city of Denver is asking voters to decide whether they would be willing to pay increased fees to keep these services that could otherwise see cuts.

Denver needs to come up with $120 million over the course of 18 months to help balance its budget. City departments tell 7NEWS they are already lean and trimming more fat could be a challenge.

"By law, we could just go ahead and assess it. We could pull a fast one but we're not going to do that," said Mayor John Hickenlooper.

Hickenlooper admitted that fees and taxes were two sides of the same coins but said he hoped fees would lessen the burden on taxpayers already struggling with shrinking budgets.

Still, Jon Caldara, president of the Independence Institute, said politicians should just be asking the voters for more money if they want it.

"Politicians are trying to pull a fast one over on us. If they want the money, all they need to do is ask for it. Instead they are calling everything a fee," said Caldara.

Caldara said his wallet can't tell the difference between a fee and a tax and said its disrespectful to constituents, who should be concerned.

Caldara said cities should contract services out, spend less and find savings before putting the burden back on taxpayers.

Hickenlooper said he was not ruling out the possibility of going to voters and asking for a tax hike but hopes a review of departments and fee increases will help them avoid it.