There is a topic about printing your own postcards, with experiences, maybe it could interest you @ahnok123
(I personally think photo with a sticker is still a photo with a sticker 
so I suggest making them to ānormalā postcards, to cardstock. )
Here is the topic:
(I have received cards printed by the moo and the quality is super good 
personally I didnāt know what was what side, so I got nervous ordering, and didnāt.)