But how have the rest of League One been faring in these financially difficult times?
Here we list the arrivals and departures of the clubs who will try and stop Posh winning an immediate return to the Championship. We also rate their transfer business out of 10.
All transfers logged by the BBC from the end of last season and up to and including June 30.
Departures listed are those who have found new clubs.
All transfers logged by the BBC from the end of last season and up to and including June 30.
5. BURTON ALBION
Ins: Davis Keillor-Dunn (Oldham). Outs: Michael Bostwick (Stevenage, pictured). Summary: Quiet and not much money about at Burton. Keillor-Dunn scored goals in a bad side so could be anything. Bostwick is well past his best so no real loss there. Transfer business rating: 5/10. Photo: Joe Dent
6. CAMBRIDGE UNITED
Ins: James Holden (Reading), Saikou Janneh (Bristol City). Outs: Jack Iredale (Bolton, pictured, left), Liam Bennett (Walsall). Summary: Lost a good player to Bolton and Wes Hoolahan has retired. Kept hold of a top goalkeeper (so far) which was important. Transfer business rating: 6/10. (Photo by Charlotte Tattersall/Getty Images). Photo: Charlotte Tattersall
7. CHARLTON ATHLETIC
Ins: Eoghan O'Connell (Rochdale), Mandela Egbo (Swindon), Joe Wollacott (Swindon), Conor McGrandles (Lincoln). Outs: Conor Washington (Rotherham, pictured), Ashley Maynard-Brewer (Gillingham), Ben Purrington (Ross County). Summary: New manager Ben Garner has raided his old club, but as Swindon failed to escape from League Two it's hard to see why that would be beneficial. McGrandles was a good player in a good Lincoln side though. Transfer business rating: 6/10. Photo: Joe Dent
8. CHELTENHAM TOWN
Ins: Dan Adshead (Norwich), Tom Bradbury (Halifax). Outs: Scott Flinders (Mansfield), Will Boyle (Huddersfield), Charlie Colkett (Crewe), Andy Williams (Walsall, pictured right). Owen Evans (Walsall). Summary: Lost the promotion-winning manager to Barnsley and the star centre-back to Huddersfield. Promoted the first-team coach Wade Elliott to keep disruption at a minimum. Transfer business rating: 6/10. (Photo by Pete Norton/Getty Images). Photo: Pete Norton