I think a $40 voucher is pretty generous - is it really necessary?
In the UK our switchover is phased and starts later this year (
http://www.digitaluk.co.uk) - although there has been some talk of assistance of elderly and low-income groups this hasn't been completed the finalised.
I'd hope the cost of the boxes didn't go much above $50 though - we can already buy cheap DVB-T boxes here (see
http://www.amazon.co.uk/DIGIHOME-FRE...4503494&sr=8-1 - £24.67) so I would imagine the economies of scale in the USA would allow similarly cheap options.
I think manufacturers in both the USA and the UK have however been very poor at continuing to provide only analogue tuners rather than twin-tuner TVs - they should have been doing this for the last few years really.
Alan