To see if you like the process but don't want to spend a ton of money:
$5-8: Dollar acrylic paints at a craft store. Get primary colors, black, and white
$2-5: Any brush set that has at least a pointy brush and a fuzzy looking brush
$5-10: Either a single mini like a DnD character mini, or to see if you like army painting get a bag of green army men
And you're good to go! Thin the acrylics with water, abuse your cheap brushes, learn dry brushing, and attempt to make and use a wash (basically just very thin paint sometimes with a tiny amount of soap). If you want to get fancy with bases grab some dirt, rocks, and twigs from outside then stick them on with thinned down white craft glue.
It's mostly learning tricks. The very high end stuff takes great skill, but you can get good results by just knowing enough to water down your paint and do some drybrushing.