Buying used Directv Receivers from Ebay. We already subscribe to Directv with 2 rooms/receivers activated?

If I am gettign this correctly you already have 2 receivers and want to purchase a third receiver so you can use any of the three at either your apartment or your motorhome. Okay as long as you have a valid access card for all the directv receivers they will work at any location you have a DirecTV dish already setup. Here is what I do just so you have an idea. I had DirecTV setup at my house, my parents wanted to try DirecTV out. So I installed a DirecTV dish at their house. I purchased another DirecTV Tivo Receiver from DirecTV. I then plugged it into my parents house's DirecTV dish. It worked perfectly, as long as it was on my account and I paid for all the receivers it does not really matter where you connect them up at. Secondly, I have a Extra DirecTV Dish that I have set up on a Tripod. I take that dish with me while camping out in the desert. I take one of my DirecTV Tivo receivers with me on the camping trip and plug it in to the DirecTV Dish. Sometimes I need to make sure that the Dish is pointed in the correct direction of the sky for the ZIP code I am in but it always works perfectly. I will let you know that when you purchase new receivers from Ebay or anywhere then DirecTV will REQUIRE you to purchase a NEW subscription card for it. They cost $20 per card, then DirecTV will add the Receiver/DVR onto your account. Once you own them you can activate them or deactivate them whenever you want online and you will NOT need to purchase any new cards or anything later on. The cards get MARRIED to the receivers now, that is why you cannot switch the cards into different receivers, it will let you know that the wrong card in inside of it. I hope this helps, please feel free to send me an email if you have any further questions...