Tilbury Cruise Terminal is part of the Tilbury Docks area, which is a completely industrialised zone of several square miles. There's absolutely nothing there except warehouses, vehicle compounds and industrial units. It's one of the most depressing places in the whole of the UK, with the nearby towns (such as Grays, where 'upmarket shopping' probably means going to Poundstretcher instead of Poundland) being very little better.
A bit of googling shows that you're not the first to ask this question and I've not been surprised to see that nobody has been able to respond with a positive answer to it.
All I can suggest is that you try to save some money by staying at a Travelodge
https://www.travelodge.co.uk/hotels/69/Thurrock-M25-hotel
Ibis
http://www.ibis.com/gb/hotel-2176-ibis-london-thurrock-m25/index.shtml
or
Premier Inn
http://www.premierinn.com/gb/en/hotels/england/essex/thurrock/thurrock-west.html
and then fork out the £11 per night that they charge for secure parking at the cruise terminal. (Leaving your car in any other car park for any length of time around that area would seem to be asking for trouble. I've actually carried out car parking surveys in Grays and I've felt hesitant about walking around some of the car parks during the day. I certainly wouldn't want to leave a car there overnight!)