It seems you likely have a computer. Of note the RTL-SDR Blog V4 SDR (software defined radio) is $32 USD shipped.
https://www.rtl-sdr.com/about-rtl-sdr/https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/If you would like experiment with VHF/UHF reception as well, there is bundle with small dipole kit for like $10 more.
The RTl-SDR V4 is a not a weak signal receiver, but it does tend to suffice for casual SWL listening for many people. I do have much better SDRs and receivers, but admittedly, I still often use the inexpensive RTL-SDR V4 on mediumwave and HF for casual monitoring. YMMV, of course.
Regardless of the receiver, plan for a (preferably outdoor) antenna if you want to receive more than the largest commercial broadcasters. A longwire is a very basic example. A cheap 9:1 transformer, some coax with the needed connectors/adapters, and a moderate length of small gauge copper wire.
Another popular SWL antenna is the MLA-30+ active loop. The loop amplifier circuit is not great (a huge understatement), but it is an outdoor antenna that suffices for many casual SWL listeners. It comes a kit with the loop, amp, coax, bias tee, etc.
If you are limited to an indoor antenna, the HFDY loop kit on AliExpress is often like $30 shipped or less. Hang it in a window, forget the included bias tee, and power it straight from the RTL-SDR's own internal 5v bias tee option. Again, not a great solution, especially being inside, but it is likely far better than most receivers' whip antennas.
All the above said, a better place (IMHO) to start your SWL listening adventure would be trying out various online SDR receivers around the world. Get used to the basics of SWL listening, then consider if you might want to venture further down the SWL rabbit hole.
http://kiwisdr.com/public/http://websdr.org/https://www.rx-888.com/web/rx.html