The Amazon Fire HD 8 an HD 10 can play Minecraft Pocket Edition. The Fire HD 10 is a little more powerful of the two. There are "Kids Editions" for maybe $30 to $40 more which are a bit more durable. Also, I heard it said that if you break these version Amazon will replace them for free (shipping may apply), but you need to verify that. There is the smaller HD 7 version, but it is an older and weaker device. Note that the 2017 and 2018 versions of the HD 8 and HD 10 have the same specs, but the software has been updated (includes Alexa "voice AI").
As for a laptop you will likely have to spend around $300 to $400 with current sales to get something pretty decent that can be useful for over 3 years. The only limitation is that you are likely looking at 15.6" that are typically around 5lbs or more. 14" laptops would be lighter, but there are not as ubiquitous as 15.6" laptops so there won't be many if at all in that price range. Spending less than $300 well... it will probably last a year before you consider it to be slow / not powerful enough.