Collection of software defined radio (SDR) stuff
I use a RTL2832U-based USB-receiver RTL_SDR by Radioddity. It is shipped with a monopole antenna which works o.k. for most use-cases (e.g. FM-Radio, 433MHz, 868MHz). To increase the mobility of the whole setup you might want to exchange the stock antenna for a smaller version.
If you want to spend more money you might go for a HackRF One