Both of my DI teams started out with prestige in the D range (D- and D+). These were the things that worked for me:
1) Recruiting as close to home as possible. I think that makes sense regardless of your prestige, but its especially important when you've got low prestige and need to maximize your funds. Also, at that prestige, you're going to be looking at guys that are pretty similar in ability, might as well go for the lower cost options. My preferred distance was within 400 miles, extending out after the first day or so, when you could identify targeted guys.
2) Deciding which "key areas" on which to focus. At that prestige, you're unlikely to get someone that has high potential or cores (or both) in every key rating, so you need to decide what you're going to target and how that will work in your system.
For example, at PG, I focused on guys that had High BH/Pass first, ATH/SPD second, DEF third. In order to find these guys, I sacrificed PER. I switched the team's Defense from man-to-man to zone, because I knew that I might have the opportunity to get someone with great cores in things other than DEF because they wouldn't work in a man-to-man system.
At a low prestige level, you need to think about your overall team profile pretty carefully and figure out which key areas are must haves and which ones you can give up.
3) Avoiding battles- Once again, this is smart at almost all levels, but it's especially true for low prestige schools. I've just found that it's generally not worth it. I try not to go into battles unless I'm 90% sure that I'm going to win, you just don't see that very often when you have a D level prestige.
4) Being patient- While at a high DI school, the first recruiting cycle is the most important, at the D level, I usually did very little on the first cycle. It took several instances of dumping $5,000 on an opening cycle only to find myself on the considering list with C+/B- schools that I was never going to beat before I backed off. After that, I would send out small amounts to see who would be interested and then waited to see who was still open after the first cycle and go from there. I don't think that I got any lesser recruits and saved a lot of money.
Hope this helps!