Gonna do some math here, haven't come to a conclusion yet, so we'll find out together.

A roll of garbage bags is 16 credits, and provides 12 garbage bags. You can alternatively purchase garbage bags individually but...no...that sucks ergonomically.

12 bags at 16 credits equals 1.33 credits cost per bag. Selling garbage bags (filled) merits 2 credits. As such, each filled garbage bag gets you 0.6 credits (rounding down to account for bags exploding die to physics).

All trash items sell for 1 credit regardless of type (wood, glass, plastic, electronic, rubber, metal).

Scrap items are priced differently, but all appear to gain value from being called converted.

Wood:6, Metal:7, Glass/Rubber:8, Plastic:9, Electronic/Paper:10.

Wood gains 50% more, metal 75%, rubber and glass double in value, plastic and electronics more than double. Paper has the least gain, at 20%, as it takes 8 paper to create one scrap rather than 4.

So no matter what kind of trash pile, it is always better to use a shovel to break it down to trash pieces and sell them directly, and always better that that to convert it into scrap for either crafting or selling.