There are lots of deals going locally as the camps aren't that busy this season. Any of the big chains are offering deals and so are the smaller camps. Worth doing some internet trawling to see what's around. Richards camp in the Mara or Phoenix safaris for their Mara Syria camp etc etc
And other parks not on the main trail also have deals going... Like Meru, Samburu etc. Nice places available at Naivasha too....
What's your preference ... Game or beach, tent or lodge? Narrow it down a bit more and maybe I can think of some others..