Welcome aboard! You'll find many macro-heads here. You'll see many suggestions for various macro lenses. I'm a cheap bastard, so I wrote this:
https://www.pentaxforums.com/forums/pentax-lens-articles/152336-cheap-macro-b...lose-work.html which may give you some ideas. Here's maybe the simplest idea:
Buy an old A-type 2x teleconverter (TC) on eBay; it'll probably be around US$25, maybe less. A-type means it has contacts for aperture automation, but not the autofocus drive which won't help with macro work anyway. Remove the glass from the TC. Now you have a cheap automatic macro-extension tube for your DA18-55! And it supports flash, which is important. A 2X TC is usually around 25mm thick, so with your kit.lens at 25mm you'll have 1:1 magnification; at 50mm it will be 1:2. For more magnification, buy another TC.
We look forward to seeing more of your pictures. Have fun!