I've never had a cotract with Orange but they seemed so desperate to keep me when I asked for a PAC they offered me 300 minutes, unlimited texts and 500 MB of data for £8 /month (think it is their already reduced 15.50 Panther, currently available on website at 10.50/month).
I didn't tell the guy that I'd already got a contract with T-Mob giving me unlimited mins, texts, and data for effectively less cost than the deal he was offering (TopCashback paid out £101 on a 12 month contract for "Full Monty" SIM deal when it was specially reduced to £16/month. Once you take off the 101 quid it comes down to about £7.75 or less as the effective monthly fee.) I signed up at the very end of January and had the £101 arrive a week ago.
However, I have used 20-30 GB in a month with my contract on Three, and frequently got close to the 600 minutes limit each month, so unlimited data is a more important option for me than the very lowest charges :)
Someone else posted (geeky_stuff but different thread) they were offered 600 minutes, unlimited texts and 500 MB data (from O2, I think) for £8/month.
It's why I'm a bit sceptical of signing up for 24 months and paying what seems like far too much over the course of that time (at least for some phones). Have seen T-Mobile contract at £17/month for the Sony Xperia Tipo, but if you buy the Tipo on T-Mob PAYG it is only £49.99 now (+£10 top-up). Just need to unlock it and then have the choice of mobile tariffs...
If you can get a cashback deal some work out to be below £5/month so for a year you'd spend maybe £150 including getting the phone unlocked, and could switch to another network at the end of that time if they had a good deal running. With the phone in a 24 month contract, it'd cost up to £200 for each year and the phone would have no resale value (as it was only quite a low cost in the first place on PAYG).
With some "redemption" deals (eg Tipo on T-Mob at www.e2save.com) you can get the phone included on a similar tariff (200-300 mins, unlim txt, 500 MB) for £12-£13 but would be tied in for 24 months all the same and the monthly DD would still be around £17 with the onus on user to reclaim cash every few months to drop the effective monthly cost.