get a parent club, they will send you some quality players on loan.
Absolutely agree

Pre-season friendlies against your parent club raise finances, get the loan agreement and not only will they send you players on loan totally free but also be much more agreeable to letting you loan players you want for 10% of their wages. Sad thing is that there's a limit of 2 players from one club allowed to be loaned in. My current Bury team has a few 'parent' club agreements, the majority for pre-season friendlies with other northwest clubs but a loan agreement with Manchester City

That was already in place when I moved there, so was one of the pleasanter surprises

Sadly, your board will not always agree or not be able to find a club to do this. Try once a season til you get one though - they just tell you to clear off if you ask them again sooner.
Players in the lower leagues tend to vary wildly from game to game. A good youth academy (cup runs to raise the money are always useful

) should get you a couple of good prospects every season. Get the best scouts you can and scout as often and as frequently as you can to spot the bargains.
The trials matches in late pre-season are good places to spot bargains released by the big clubs.
Try not to go too mad bringing players in, just cos they're freebies - you need some squad harmony or your first few months might be rather rocky.
I'm currently a year into managing Bury (moved there Christmas last season from my promoted Newport County). They were bottom of the table, 800k in debt and stank like only a league 2 team heading out of the league can. Finished 15th, this season at Christmas in a solid playoff place with hopes of automatic promotion, and debt is down to 200k with a nice 3rd round trip away to Swansea next up. Most enjoyable way to learn the game for me is to start off in the Blue Square North/South and gradually work my way up the career ladder to get to the Premiership.