As this issue KEEPS coming up (in various variations) . . .

For people starting from "scratch" in kilts, there are SO many accessories and SO much $$$ involved to get them that we MUST make priorities.

I think that the highest priorities should be on good quality belts and a sporran, all in the same color. I like black, personally, and think those are the most adaptable for different dress levels. There ARE QUITE different types and levels of belts. A GOOD quality one will be usable for YEARS to come. The same with a sporran. Most barely acceptable belts are either work belts or bought "dress" belts, both of which tend to be VERY stiff (not very comfortable for everyday wear). I'd recommend a good, softer, wide one for use with a kilt. I HAD some crappy one, but once I got a decent one I NEVER have worn it again. So, that initial out lay is now WASTED. The same is true with sporrans. In BOTH, I'd recommend getting ones that will last as your kilts get nicer. A good quality set WILL last you for A LONG time. BUT, crappy/cheap ones will be tossed AS SOON as you get nicer ones. For the outlay, THESE are the BEST quality improvement for cost difference.

As for shirts, hose, flashes, and the like, these are basically disposable and can be "upped" in quality latter. You WILL get more anyways, as you wear kilts for YEARS. If I HAD to skimp, it would be on these. You can continue to use the initial stuff later on too.

The kilt itself will be based on your interest and level of finances. I'd say get the best you can afford, BUT people get what they want and most own more than one. Some of us even make our own.

As for shoes, sgain dubhs, Argyle jackets, bonnets, and a few other things, they can be gotten later and are not NECESSARY for kilting. They are also expensive. If you are tight on cash, I'd wait and get them later.
I'd include kilt pins in this section too. I have a number, but usually wear NONE (except when "dressing nice." For most times, they are just too risky for catching and snagging things.