To create sfx, any DAW can work, Ableton Live, Reaper (free) and ProTools work really well, but any can do sound design. As for how to do it, there is many ways. First, you can create sounds with synth and vst, it's hard, and in that way yes 8bit is easier to do. You can also use something from a sound pack (sound ideas is one of the best) or a ripped sound pack from a game, then you modify it to make them fit in your game (with time stretch, reverse, treatment and effects, pitch shift, morphing, everything is possible to transform a burping sound into a huge explosion). This option is the most common in indie development. Finally, you can record sounds around you, and modify them the same way you can modify the sounds from an audio pack, but this time it's 100% yours. You have a lot of tutorial online on how to turn a sound into an other. Of course to record you need some equipment, but a Zoom H6 recorder isn't that expensive nowadays, and it's something you will use a lot. You can also simply contact sound designers, I'm sure there is a lot of them who would love to work for you on future game jams!
Viewing post in The Antartes jam comments
oh wow yeah it's expensive... maybe try to buy it used, a lot of time used stuff is correct on the audio equipment (these things are solid) You can still start recording stuff with your phone, it will just not be as good sounding as if recorded with a pro audio device, but it'll be a good start. You can also train to modify sounds from youtube or sample websites