I bought all of them. I have no regrets.
But if you can't part with much money, let me recommend a few:
Infinite Regalia - A difficult map, but one that provides an infinite source of powerful items. It doesn't give them to your outright, because a powerful army stands in your way. I quite like that.
Lost Bloodlines 2 - Beating this one nets you the Demon Scroll. It allows you to change a male unit into a Dread Fighter, which is ideal for some characters.
Smash Brethren 2 - Like LB2, but replace Demon Scroll with Wedding Bouquet, Dread Fighter with Bride, and male with female.
Rogues & Redeemers 3 - A tough map that I managed to beat with only a paired Chrom and Lucina. Beating this unlocks Ike (awesome) and the Limit Breaker skill (all kinds of awesome).
The Scramble Pack - Get this if you like the characters and really, really want to see more interactions between them. Also if you have a penchant for the ridiculous.
The Future Past 1/2/3 - The only DLC that adds something to the main plot. Very neat. Very worth your time.
Apotheosis - This is the obligatory ultra-tough map.
3DS Friend Code: 0645 - 5827 - 5788
WayForward Kickstarter is best kickstarter: http://www.kickstarter.com/projects/1236620800/shantae-half-genie-hero
