Well regarded Canon 400D SLR with 18-55mm lens can be bought for an effective £372.50 using the £50 Canon cashback and the current Advantage points offers: Triple points and 1000 extra if you spend £50 or more along with the 750 bonus voucher (7749 points).
The downside of the promotion is that you have to pay £499.99 up front. You then get £50 from Canon and 7749 Advantage points (if you have not already used the 750 voucher), equivalent to £77.49. It's still 6999 Advantage points even without the extra vouchers so still a decent deal if you want the 400D in the next few days, provided you do shop in Boots stores on the High Street.
It can even be as low as £355 if you use 3.5% QuidCo (£17.50).
Not for you if you don't use Boots stores or cannot spend the £499.99 now or do not want to wait for your £144.99 to get back to you.