If you cannot afford Amiga Forever, use the open-source AROS ROM. It will boot an Amiga 1200 emulation well enough to run productivity software and some open-source games, though classic commercial games may glitch.
Each Amiga model shipped with a different Kickstart version. A proper collection includes: amiga rom collection
The best $9.95 you will ever spend. (from Cloanto) is a legal emulation package that includes fully licensed Kickstart ROMs for every Amiga model, plus Workbench disks. It provides the ROM files in .rom format that you can copy directly into WinUAE or RetroArch. If you cannot afford Amiga Forever, use the