Thanks for the additional information. I really appreciate it.
With skin tags, as a general rule, as long as it doesn't cause the dog discomfort, and doesn't actively bleed regularly, we tend to just keep an eye on things.
However, since you said it has been growing, then it's not a bad idea to have your vet take a peek and determine if he thinks that it's something that needs to be removed, or if it's something that you can continue to monitor.
There are some organizations that might be able to help. If you'll follow these links: http://www.speakingforspot.com/helppayingforveterinarycare.html , http://www.theamericandogmag.com/non-profit/resources-veterinary-bills-financial-assistance, you'll find dozens and dozens of organizations that may be able to help pay for you to take your dog to the vet. Also, there are some clinics who offer free exams and other treatments and require that you only pay for medications. If you'll follow this link: http://www.vcahospitals.com/main/offer , you can see if there is one in your area.
Odds are this is nothing to be concerned about, but having the vet take a peek will give you the best peace of mind.
I hope this helps.