It does appear that Disney will be providing a lower-cost saber option... in the form of repainted and slightly-reworked versions of their currently-available Jedi Training Academy sabers. On the left side of the table in this photo:
Those will 100% be cheap plastic, but the sort of weathered look is definitely an improvement over the extremely basic versions sold in the parks today.
I'll be interested to see reviews of the custom sabers once people get into the land; the word of mouth (and exact pricing options for the customs and the Legacies) will end up determining if I go that route or not.