ive got a bush freesat hd rx from argos. I paid £67.0 for it 2 years ago.
There are quiet a few out there now you should not need to pay more than about £75 for one. Many will extol the virtues of a humax unit , but they cost £100 plus.
All have EPG but not all have preview picture or program info on the epg but for something that ostensibly is ony used a few times per year does it really matter.
Try Maplins, and B & Q, Tesco online, Ebay,and even have a look in your local Asda(walmart), or Sainsbury.
Most are 12v through a 240v transformer.