I think 'pay as you play' deals are somewhat of a myth, frequently wheeled out by football fans.
I think the reality is that players have a contract which is 'enhanced' by things like appearance bonuses.
The likes of Sturridge and Wiltshire would command more than the likes of we could pay for their basic salary let alone appearances on top of it.
In general though you need to know what motivates these types of players, they have money in the bank, so they wouldn't be here for that, and they have played at the highest level so they would want to still play at the best level they could.
I'm not sure Sturridge and Wiltshire would want to be turning out at say Doncaster in the pouring rain on a Tuesday in November for a third tier club like us.
Very few 'top' players end their days dropping so far down the leagues, so although it might be good to dream some of our ex players would want to put the shirt on again I can't see it happening and I doubt it would turn out to be a success if they did.
Sorry to be a bit of a wet blanket about this.