I have a few Japanese pack-in Mario’s Tennis carts. Each one is complete with a dust cover. I tested all of them and they all work great. Conditions are Excellent. Most look brand new and never played/touched.
$13 each with a dust cap (+shipping/fees)
$10 each w/o a dust cap (+shipping/fees)
I also have a USA Wario Land cart and manual (no box). I booted it to make sure it works, but have not tested how long the battery may or may not store save files. Condition looks nice. The manual is complete with a corner fold, and is in VG- condition. I have a mint dust cap for this cart as well.
$25 with a dust cap (+shipping/fees).
If you need legit/retail Nintendo VB cart dust caps, I have a few extra. $4 each.
I’m in the US and have Paypal. If you (or anyone) are interested, please PM me for pics.