As one of its daily deals, Meh offers four CamelBak 20-oz. KickBak Tumblers in People for Bikes for $20. With $5 for shipping, that's the lowest price we could find for this amount by $11. (For further reference, we saw one CamelBak 20-oz. or 30-oz. KickBak Tumbler for $7 with free shipping a year ago.) They keep drinks cold for eight hours or hot for four hours.
Four 30-oz. KickBak Tumblers are also available for $28 with $5 for shipping. That's the lowest price we could find for this amount by $23. Both deals end today.
Note: These models have a logo not associated with this brand usually.
There are many ways to get cheap and even free services and goods after reaching a certain age.