Hi Sir or Madam,
Dogs can get hernias in the groin area and I have to wonder if perhaps it is a hernia rather than a growth. Depending on the size, some hernias can pushed back into place but pop back out almost immediately. You can read about hernias here:
A lump or growth is hard to diagnose even with an office visit, over the internet it is even harder as we can not even see the growth. A lump may indicate cancer, but many such growths are harmless. Many lumps are not painful or bothersome. It may be a fatty tissue deposit called Lipomas or a wart or a hematoma, but to be positive your vet will need to test the lump to be sure.
Any lump found on your animal should be tested to determine if it is a cancerous or benign lump. Your vet will want to perform a fine-needle aspiration or other appropriate test. It is performed quickly and allows some of the cells of the lump to be evaluated by the veterinary pathologist. This test will allow the vet to determine the nature of the lump and take the necessary steps to remove it. Some vets will leave it alone if it is not serious. If it is an abscess, he may just drain it and prescribe antibiotics. Lumps that are solid feeling, feel attached and fast growing should be checked as soon as possible as these are the ones that are more likely to be serious.
Here are a few sites for additional information and pictures to allow you to get an idea based on the physical characteristics..
Picture of Lipoma
Picture of Hemangiosarcoma
Picture of a mast cell tumor
http://www.vetsurgerycentral.com/mct.htm (mast tumor site)
Many vets just leave lipomas alone unless they are causing problems. I do understand having financial difficulties. There are some vets that will give a free office visit the first time, but will charge for testing. Perhaps one of these can take a look at your dog and give you an educated opinion without the need for expensive testing. Here is the list of vets that may offer a free initial visit though you may have to pay for extra procedures and medications. See the next one for the coupons.
I hope this information is helpful to you.