Does anyone know where I can find a price list for day passes for British railways-subways?

An exact link would be great.

There isn't a day pass for British Railways.

Some cities have day passes for public transport in their area - eg London Travelcard so if you give us a bit more information to work with

Basically, I will be in London four days. I might want to go to Cambridge one of the days, and I have to get back and forth to Stansted. I want use the underground, and then the train to Cambridge and Stansted. Is there any cheap, umbrella way to pay for this?

Between London & Stansted I'd look at the various coach options - Easybus, Terravision, National Express - rather than the Stansted Express. So you could be looking at around £17 for a return ticket rather than £23.50 for the StEx

Within London I'd get 1 day off peak zone 1-2 travelcards - £5.10 per day and if there's more tan one of you it means you can use the offers on www.2for1.entry.co.uk

For Cambridge why don't you do that on your first or last day - Stansted is only about 30 minutes by train from Cambridge so it makes more sense to stay there for a night

in any case there is no such one day pass i believe re BritRail.

What might work is the 2 day in 8 day London plus flex pass Both
Cambridge and Stansted are witin the covered area. Cost is $74. You can buy it in the USA.

Yes the Days Out of London flexipass - good for 2 unlimted or 4 unlimited travel days out of an 8-day period may be a good deal - especially since you can use it on any train to Cambridge, Stansted just by showing up. Yes sold only in US from RailEurope and BritRail. Yet they charge $18 mailing fee - i alwyas recommend BETS (800-441-2387) for any pass for their expertise and lack of this type of mailing fee.

Compare regular prices at www.nationalrail.co.uk - good on Gatwick Express but not Heathrow Express good on Stansted Express. Also comes in first class.

There is no railpass that will be a good deal for your itinerary.

I'll add a bit to what alanRow wrote. Booked online, the easyBus Stansted-London fare is £2. The walk-up fare is £7. As Alan says, either a Terravision coach or a National Express coach would be cheaper than the Stansted Express.

Booked online at www.nationalexpress.com, fun fares for London-Cambridge start at £1. An open same-day return (roundtrip) ticket is £10.50. The trip takes two hours.

Booked online, an advance saver same-day return train ticket for London-Cambridge can be as low as £13, but you are limited to a specific train each way. An open same-day return is £22. The trip takes either side of an hour, depending upon how many stops a particular train makes.

One more thing. Use the Journey Planner at www.nationalrail.co.uk to get timetables and fares.

Whatever you do, book and buy before you arrive. The earlier you book, the less it costs. Similiar to air flight