Insta will absolutely work for marketing purposes. Promote yourself. Wordpress websites are pretty easy but it will take some research to actually make one. If you want a more serious website you can always develop it with a web designer but you should leave that for a moment that you want to transition into fully doing design maybe. A one pager is a simple website with just one page. The advantage is that you keep it small. Anyway keep it simple for yourself and if you want to expand you can let me know and I’ll tell you all about building your own website.