Not sure what you have already (1010, holey rail?), but I decided to go with just the guide plate, holey rail, and end stops. I was able to find alternatives to the Festool router bits.
I can't comment on the 3D printed part that goes on the guide rods, I would probably have considered that but I don't have a Festool router.
If you're ambitious and really want to save money you could make your own guide plate.
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To me it seemed like the most important parts for accuracy were the holey rail, the end stops, and the guide plate, so I ended up getting the official Festool parts for those components. I feel like for the front set backs there are plenty of other solutions, like DIY set back guides (Peter Millard has a video on some simple ones out of MDF or plywood), or if you have parallel guides you could use those. I'm planning on using a Woodpecker metric paolini pocket rule to push the rail back from the front edge.
If you have access to a 3D printer, there's also
this thing, which I haven't tested or anything, but could be a cheap solution if it works well.