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 15ยข 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.