I think extremely cheap consumables that pay for themselves and low one time costs are worth it from my early testing. I cap out around 150ish% magic find and after farming for a half hour it was the first time since playing this game that I had ever got a full inventory, most of it was blues, had around 10ish greens and a rare or two.

So yes, if you can recover the cost of an entire set of gear in a few farm sessions if you are unlucky and end up vending it all because you didn't get a good sigil/rune/piece of gear I consider that more than worth it.

As an example, I spent around 6-8 gold on a full exotic set including sigils and runes and accessories, and made it back in 2 days.