Well I spent a good bit of time using a mouse and it was really annoying so I got a tablet and I eventually made all the money I spent on it back, and now anything I do is just plus so for me it was a good investment, just take things like that into consideration like will you be using it to make money or just for fun if you decide to get one.

Personally I'm glade I got one and it was a good investment for me.
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Oh btw I have a Wacom bamboo pen and touch medium size- cost me $100 it's fairly cheap and good quality I'd recommend getting that one if you decide to buy one
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An example also is I'm doing a concept art for someone for $20 and little jobs like that here and there really add up
Ps I'm going to keep the name of the person and picture privet because they most likely wouldn't want me sharing that stuff

I just thought I'd add this as an example to show how it "could" be a good investment over time and with practice