I would agree with the others, either the Tactic 8-channel or the FrSky Taranis. I believe the Tactic would be easier to get started with the programming since the Taranis has a bigger learning curve because it has so much more programming capability. The receivers for both brands are quite reasonable in the $20 dollar range for 6-8 channels.
But I would also suggest that you go to the club you will be flying from and ask around what the members are using, especially the instructors.