There are only a few hotels in Maradi, and none of what might be truly considered 'budget' hotels. Nigeriens are not avid travelers, as a general rule, and when they do travel, most make arrangements for accommodation with the family member, friend, agency, or co-worker that they are traveling to visit tourism for the sake of tourism is a concept foreign to most Nigeriens; you are likely to be regarded with a touch of confusion or even interested surprise if you explain that this is what you're doing. For this reason, many of the aid and missionary organizations that work in Maradi have their own accommodations for their people when they are in town; if you happen to have a connection to such an organization, you might do well to inquire, although many of these agencies have fairly strict standards of use.
If you need a hotel, consider the following:
Hotel Jangorzo
+227 20 410 140 - also pricy, but also nice.
The Guesthouse
+227 20 410 754 - most expensive and also nicest hotel in maradi.