The very same questions I asked 12 months ago.
Filament is a very personal preference. If it is winter where you live now, avoid ABS. ABS is very
fussy about room temp and unless you have a heated compartment on your printer, every print
will warp off the print bed. Nothing puts a person off of printing quicker then having every print
warp.
PLA is a good starting filament. Fussy and slower then ABS. Still warps but not as much as ABS.
PETG is my favourite currently. It will simply not warp at all and none the nasty fumes of ABS,PLA.
Downside is it is more expensive then ABS,PLA. Can be close to twice the price of the others.
Don't scrimp and buy cheap Ebay no name filament. It'll bite you on the butt.
Stick with 0.4 to begin with. Forget about 0.2 until you become REALLY good with a printer. I've got
about 30 spare nozzles of different sizes and haven't used anything other the 0.4 for a few months.
Slic3r is rather overwhelming to begin with.Kisslicer is minimalist in design and simpler to begin with.
Kisslicer generates quicker prints but Slic3r gives you more control over the prints.
Only ones I've used.
Heat ABS prints and cool PLA, so close for ABS and open for PLA. My PETG doesn't seem to give
a damn about bed cooling.
