I believe that the topic of Weathertech mats for the Bolt was covered elsewhere in the forum, but since the information was scattered a bit, I'll consolidate it here in case people are looking for it.
Cargo tray. Go to www.weathertech.com/chevrolet/2017/bolt-ev/cargo-liner
Answer "No" to the question "Is your vehicle equipped with the false cargo floor?" You can now purchase the fitted cargo tray (aka trunk liner) for the Bolt, part number 401012. Ignore the random photos on this page, which are for a different product. I bought this liner myself and it fits into the trunk perfectly.
All-weather mats. Go to www.weathertech.com/chevrolet/2017/bolt-ev/all-vehicle-mats-avm
I bought the 3-piece option (part number 11AVMOTHSB), which offers slightly better back-seat coverage than the 4-piece option (part number 11AVMSB), but also requires more work to trim. Either choice will fit the Bolt very nicely.
When your mats arrive, you'll need to do some manual trimming using large scissors. This can take some careful trial-and-error, so allocate at least an hour. If you ordered the 3-piece set, then you'll need to trim both the driver's mat and the back seat mat; the front passenger mat fits as-is. If you ordered the 4-piece set, then you'll only need to trim the driver's mat; the front passenger and back seat mats both fit as-is.
Examples are shown here: www.electricvehiclewiki.com/Chevy_Bolt_Floor_Mats
If you prefer, instead of the regular all-weather mats described above, you can order heavier-duty mats (part number 11AVMSBHD) here: www.weathertech.com/chevrolet/2017/bolt-ev/all-vehicle-mats-avm-hd