I get my 1mb broadband and telephone rental and all local and national landline calls for just under €47 per month. The broadband part of that bill is under €17 per month. I send most of my texts using the free ones online - vodafone give 300 per month to registered users. How dearly are you wedded to not having a landline, and is there a good reason for you not having one?
How well wireless broadband, the kind without a landline, operates can be completely individual to each location, so to find someone 300 yards away getting a great service doesn't automatically mean you will. You'll only know for sure when you try each suppliers system out.
Think about getting a landline.