If you are staying at either the ibis or ibis styles at heathrow airport, do NOT take the white colored hotel hoppa bus as this is a rip off. The hoppa bus charges 5 british pounds one way and 9 pounds to go and come back. A family of four would spend 36 pounds just on the bus travel which is more expensive than even a taxi.

You can get to either ibis hotel (and back to the airport) FOR FREE using the local red colored buses. These are all free of charge in the roads around heathrow airport. If in doubt about where to get off, ask the driver. They are very used to people using them for the hotels.

One exception is bus number 90 which charges 1.50 per journey. No cash...just payble with an oyster card or contactless debit/creditcard. Still a lot cheaper than the hoppa bus though.