You're not alone. And as far as I'm aware, there's no way to get them cheaper as their price hasn't dropped and they've never gone on sale.https://www.reddit.com/r/masseffect/comments/3gdzbs/lets_talk_about_mass_effect_dlcs_cost/https://www.amazon.com/Mass-Effect-Collection-Online-Game/dp/B00HQLEITK
The problem is that the Digital Deluxe Edition of ME2, which you would think would have the DLC. Doesn't. So it's kinda ridiculous to get the DLC otherwise.
Yeah I spent like 30 bucks to get all the DLC. Kind of a rip off but I love Mass Effect so I don't care. Speaking of I need to fucking finish Mass Effect 2 and buy 3.