SuperNova on 30 May 2016
I basically second hershel_laytons list, but I have a few additions.
He mentions the Professor Layton trilogy and Professor Layton vs Ace Attorney, but not the Ace Attorney series itself. You can get the original trilogy remastered on the eshop for 29$ (I think) but it goes on sale often and you can probably get it for 15$. There's also the newest game Dual Destinies, wich is imo one of the best of the series.
I'd also like to recommend Zelda a link between worlds. It's a select title, so you can get it cheaply and it's one of the best handheld Zeldas.
Be sure to check out the virtual console as well. The prices can be a little steep but there's a lot of gems on there.
