Hi @hopefully2021
I live in Horndon, which is not too far from Grays and has been mentioned above as a potential area. It is lovely, but you won't get anything in your budget to live if you are after a house, I am afraid. 2 bed flats go for about 280k, houses for about 400k plus and anything in this kind of bracket sells within 1-2 days, so if you are keen keep an eye out!
Same goes for Orsett and Bulphan. Brentwood, Upminster, Havering etc are even more expensive.
Stanford-Le-Hope isn't too bad, but avoid the high street area around King Street. Either near Homesteads, or Wharf Road and the side roads off it are quite nice.
Corringham isn't particularly pleasant, but the road leading to it from Stanford is okay. Fobbing is nice, but may not be in your budget. Basildon town centre area is not great, but areas like Noak Bridge, edges of Laindon are okay. Would avoid Vange//Pitsea.
Grays, I am afraid, is a horrible area. Very rough, not safe to walk around really and just not a nice feel. How about North Stifford, West Tilbury or parts of East Tilbury?
Chadwell St Mary I would avoid, as I would Chafford or Purfleet. Traffic round there is an absolute nightmare often, due to the bridge and is only due to get worse. You may encounter problems with the A13 anyway, as they've been widening it for what feels like forever and there is constant traffic in rush hour. At least with some of the towns like Laindon or Noak Bridge you can use the A127 as well, although that can be equally as bad!
Haven't been to aveley in years, it wasn't the best. South Ockendon is horrid, souless, and rough.
Hope this helps - I have lived in Horndon for 30 odd years so know the area really well, and have family in Grays, South Ockendon and Basildon.
But you're right to come and visit, there are small pockets of niceness in area but few and far between.