Reach out to bloggers in this niche. If this is something that doesn't exist in some capacity and can really help people, maybe some bloggers will mention it and you can get a few subscribers.
Look for parallel partners. Maybe you can negotiate where someone mentions your daily deals in their daily deal email and you can mention their deals in four of yours to mitigate their risk.
Trade resources for mentions. Maybe you have a specific expertise that you can sell to someone in a similar space. Instead of charging money, barter a mention in their newsletter or blog.
Start a blog and create catch titles that people can get attached to in your niche. Something like 8 secrets to a free vacation in Dubai can go viral.
Write featured blog posts for related blogs. This is nice because it usually guarantees an existing audience will read your post.