I can not give you suggestions as to WHERE to buy, but I can tell you where I have bought.
I have a few of a brand called ECO-LED, I got them at RV dealers, they are expensive but very very good, Brighter than a 1144, close to a 1156 (for the equivlent part) I use the disc shaped ones that shoot sideways to teh socket on a bayonet (1141/1156) socket.
I also have a round job I got from RVbyFred (Fred brandburg) cheaper and every bit as good.
I also have one I got for fifty cents off a close out table.. But that is a "Find".
Now my advice: Shop around and buy JUST ONE lamp assembly from each dealer who's deals you like.. Do not spend more than 15 bucks for a 1141/1156 replacement.
Try it.. I've seen some LED replacements that I'd not give 15¢ for, and some which were if anything BRIGHTER than the 1156 they replaced.
NOTE that the shape of your fixture affects which LED assembly is best as well.
Finally.. Tune in a WEAK FM radio staion and see if the LED wipes it out.
Keep a list of each lamp you buy and where you bought it from.
IF it turns out to be a "Dim bulb" then.
Paper list, BLACK MARKER over the seller's name (Or line thorugh with apen.
Computer list: Strikethrough the seller's name
When you find one you really really like.. BOLD PRINT.