yuba mundo chain tensioner

[PretendGentleman]

I'm wondering if anybody has used an effective chain tensioner for their Yuba mundo or similar cargo bike.

Hopefully something cheap!

I imagine a floating pulley half-way between the chainring and cassette would work well.

I've seen this: Bionicon C-Guide 19g Bicycle Chain Guide Retention System Black MTB V.02 | eBay
but its a bit pricey. anything cheaper? diy options???

[ThundaCrymz]

DH DOWNHILL,MTB MOUNTAIN BIKE CHAIN GUIDE,TENSIONER,NEW | eBay maybe something like this ?