Hi I am in Eccles so not far from you, can help with some stuff. I would try venues own by the council first they are generally cheaper than some hotels. In Salford we have Buile Hill banqueting suite which is big and in the middle of a park have done a few wedding there its a lovely spacious place and the food is good, also I think you can have stuff like a curry or hot pot or bacon barms for the evening which is usually cheaper ,Also Worsley Court house is lovely if you want an old building and I would imaging the prices for food are the same .
http://www.salford.gov.uk/leisure/venue-hire/worsleycourthouse.htm
http://www.salford.gov.uk/leisure/venue-hire/builehillhall.htm
If you are a rugby fan , or even if you are not! Salford rugby club do a really good package at the Willows which can include the cake and table decs etc too
http://www.thewillowsonline.co.uk/
you will get loads of help on here and lots of budget experts !
this site is my daughters (with my cakes) and she is happy to try and work to any budget if you need any of the services on there its always worth a chat
www.asixpenceforhershoe.co.uk