Building on the earlier suggestion, I've tried many budget setups over the years and honestly, the hiss usually comes from the camera preamps being pushed too hard. The Saramonic VMic Mini Cardioid Condenser Microphone is a total sleeper hit for the M50.

• Higher sensitivity helps keep your gain low
• Small enough to not block your screen Its served me well on quick trips. Just remember to kill the auto-gain in the menu or itll still hiss like crazy... safe travels!

Saw this earlier but just getting back to you! Honestly, I had a total meltdown when my gear failed right before a big shoot last year, so I totally get the stress! I ended up snagging the Takstar SGC-598 On-Camera Shotgun Microphone for about $30 and it was a literal lifesaver! I love it because it has a +10dB gain boost switch on the side which is fantastic for the M50 preamps. Basically, you turn the camera gain down almost to zero and let the mic boost the signal... it completely deletes that nasty hiss youre hearing! Its a bit bigger than the tiny ones but the sound quality is amazing for the price. Just grab some AA batteries and you are good to go for Japan! Seriously, it saved my butt and I still use it as a backup today.

Late to the thread but i totally get the panic... I once had a mic cable fray right before a wedding shoot and had to improvise with a backup that cost twenty bucks. Before you pull the trigger tho, are you mostly gonna be filming in crowded spots like Shibuya or quiet temples? The background noise levels will change which mic works best for you. For pure reliability under fifty bucks, check out the Boya BY-MM1 Compact On-Camera Microphone. I used one for a year straight and it held up better than some of my more expensive gear.

• Build quality: Its a solid metal body. Most budget mics are flimsy plastic that breaks if you bump it in your bag.
• Simplicity: No batteries needed. Since it runs on plug-in power, you dont have to worry about it dying during a long day of sightseeing.
• Sound profile: It has a decent cardioid pickup. The hiss is usually the camera preamps struggling. With the Boya, just make sure you go into your M50 settings and turn off the auto-levels. Set it manually to about 25 or 30 percent and you should see that noise floor drop significantly.

Since you are heading to Japan in four days, you really need a solution that is reliable and doesnt require specialized power. The Canon M50 Mark II has decent preamps, but the hiss is usually caused by the camera trying to boost a weak signal. To stay under your 50 dollar budget while ensuring quality, I recommend these two options based on my own testing:

• Movo VXR10 Universal Video Microphone with Deadcat Windscreen: This is probably your best bet for travel. It is compact and, crucially, it does not require batteries. You dont want to be hunting for AAA batteries in a 7-Eleven halfway through your trip. The cardioid pickup pattern is tight enough to isolate your voice while still capturing some ambience.
• Takstar SGC-598 High Sensitivity Shotgun Microphone: While it is much bulkier, it features a +10dB sensitivity boost. This is the secret to killing the hiss on budget Canons. By using the boost on the mic, you can turn the Recording Level in your camera settings way down. This bypasses the noisy internal amp.
• Handling noise is the main trade-off at this price point. Make sure the shock mount is secure before you head out. I have used both and the Movo is more convenient for vlogging, but the Takstar technically sounds cleaner if you manage the gain correctly. Honestly, just grab the Movo so you have less gear to carry. It fits the M50 size much better and wont feel like a giant antenna on top of your rig.