Best place to buy blower fan for gas furnace? Motor is still good just need Shroud and blades. I don’t even know where to get a part # from?

junkyard, if you're lucky

if not, have the parts fabricated in a machine shop

Not a good idea to mess with gas appliances unless you know what you are doing. May even be illegal if you are not qualified.

don't worry about carbon monoxide poisoning ? replace the furnace I recently  lost a few family members to carbon monoxide rust holes in the fire box was the cause the unit was maybe 15 years old. What does a new unit cost?

Look at the Make of the furnace and locate a supplier first in YOUR Town.  Use the phone book  Yellow pages and look under Plumbing/Heating suppliers or shops.  Chances are good this is a repair job not a replacement. Shrouds or blades don't wear out. so you are going to have to hope they got an old one out back that they are taking parts off of.

My blower fan is a squirrel cage which most are so they really need to know the IDENTITY of the gas furnace.  This looks like it fits in a trailer, not a house?

That is an inducer assembly for creating a positive draft,  part is packard 66005

Best to look for a used furnace for parts or install if you're on that tight of a budget. I doubt you'll find new parts for that. If the fan or shroud is broken you may be able to have them welded up.

What does that have to do with this forum on AUTO REPAIR?