No, when you file a trademark application in the US under a "use in commerce" basis, it doesn't cost extra. In fact, it's actually cheaper than an "intent to use" application when factoring in all the fees.
The "use in commerce" option means that the trademark is currently being used in commerce in the US market. When submitting your application, you will also have to provide proof (specimen) of this commercial use, such as product packaging, website screenshot, advertising materials, invoices, etc.
If the trademark you are registering is not used in the US market yet, but you have a genuine intention to use it in the future, you must apply under an "intent to use' basis". In this case, you will have to prove to have started using the trademark within a certain time frame after registration. The submission of the specimen will be subject to additional fees.