Schneiderlin had plenty of Premier League experience and counts as homegrown. I don't think United bought him to be a long-term starter, but £20 milion is on the cheap side for someone like him right now relative to the state of the market.
Generally I think English clubs overpay for central midfielders though. There's plenty of talent around if you care to look. Delph is getting laughed at since his City move for instance, but he's an excellent footballer at heart. Gueye excelled last season in one of the worst sides I've ever seen in Premier League and deserved a better club than Everton. Cabaye was great for Palace last year and would have been a good short-term solution for pretty much every top club in the country. Leicester brought in Kante from France last summer for like two million quid.