Which are the nearest budget places to stay near the Homewood campus of JHU? is there any B&B,Hotel,Motel, Homestay nearby which is in a walking distance?
There is a hotel next to campus but not budget. Otherwise, you are staying downtown or in Towson area. Without a car, downtown is best option. Everywhere will between mile and 1.5 miles to campus.
You don't want to stay there. Pick a hotel downtown. There are holiday inns, sleep inns, which are budget and convenient.
The Doubletree Colonnade adjacent to campus is a bit fancy, but it will only be slightly more expensive than staying at a hotel downtown. The Ramada Limited West Bmore is going to be budget and maybe run down. Public transit from there to JHU Homewood would be a huge hassle. I would advise against that.
If price is a big of a factor, try for a room at the Baltimore International Hostel/Hostelling International-Baltimore and take a bus - I think #3 - up Charles St to get to the Homewood campus.