This is from someone who's just learning.
I didn't want to invest in a dehydrator, so I dried basil, thyme, parsley, dill and celery greens (individually, of course) on a cookie sheet in my electric oven on the on/off cycle. It took at least several hours.
I let it sit overnight then tested it to see if it was nice and crumbly. Once it was all totally dry, I packed it in spice containers I had saved.
It worked beautifully!
And home dried herbs really do taste better! I especially look forward to doing thyme again.
So, very, very cheap. No special equipment and I got a product I use.