If it has a narrow band radio, you could go ahead and fly it until you are ready to move up. DO not spend more money on THAT radio to get it modified to narrow band though, a new radio would be batter use of the money. What Mfg and model of radio is it? FM or PCM would be better for your next radio choice. The engine can be removed and soaked in warm antifreeze overnight (in an old crock pot or something like that. NEVER eat from that crock pot again though) That should loosen it up. Rotate/move things while they are warm to loosen the congealed castor oil. When done, you can lubricate the engine for until you are ready to use it. While this may not be a GREAT bargain it is a fairly good deal. It would be very difficult to duplicate assuming everything is in the indicated condition. It looks like you could be flying for just a few dollars more. You will need fresh fuel and you will need to evaluate the batteries in the radio system for possible replacement. See if you can get the seller to charge the radios and show you that they work. Batteries may still need replacing but at least you will know electronics work. Used gear is always a crapshoot in some ways. Some things you know are OK and some you guess at.

Good luck and welcome to the hobby.