No webapp currently, and there probably won't be. The costs of hosting would rise without increasing market penetration.
Like /u/marcustalbot1997 said, you can get an Android emulator for your PC(and probably Mac/Linux). I prefer Nox, which after I looked at it is available for PC and Mac.
Be sure to pre-register on Google Play!
https://play.google.com/store/apps/details?id=com.retoragames.merchantheroes
Are you in a country that supports google opinion rewards? https://play.google.com/store/apps/details?id=com.google.android.apps.paidtasks&hl=en
It's a great way to support mobile game habits :P. I usually average about 2-3 dollars a month or so, which helps a lot with buying little cheap but useful apps/games and any small IAP they have (like merchant). Surveys take no time at all and are usually very basic "have you heard of any of these brands? have you visited this store type recently? how was your experience 1-5 stars?". Occasionally dry spells of no surveys for a long time but then get them again.
As for farming gold, GrinderKnight has a great strategy he shared if you can handle the weekly bosses: https://www.reddit.com/r/MerchantRPG/comments/4gfuq4/200k_gold_in_one_week/. Basically farm and make whatever you can from what the weekly boss is -- usually generates a lot of gold pretty easily.
oh I found our competition...if you could call it that. here is the link to Shop Heroes. Take head of things that you DON'T want in Merchant. Things like gems..
I don't know if this will work, but its all the T1 craftable items and drops. It is the list (minimum) price, so they can and do sell for more.
I really like Helium, from Clockworkmod: https://play.google.com/store/apps/details?id=com.koushikdutta.backup
It does not require root and has a free version (doesn't allow backup to GDrive/Dropbox).
Jacksmith! Really fun game. Our soundtrack didn't come from Jacksmith though, it was posted as a free to use song by a musician a few years ago in an indie game dev group, and we used it then. I'll try to track down the source at some point, once we add real credits to the game.
Wanna get a head start in Merchant Heroes?
These keys unlock the Starter Pack for new installs.
2Z3QAFFWXCLMLTDTQWQSFG9
DAUPNK248U0TWHJETNDVDH6
MUQ4VPBYFC1JRZQ7T648Z36
​
And here's one Silver Pouch for whoever is lucky enough to snag it!
JEGNLDVA6DMHRBY8AWH7783
I have a FIX update! I figured out how to fix this. I'm super excited. It's kind of a back-road version, but it works.
Go on your computer to the Google Play store - Here's the direct link for the game https://play.google.com/store/apps/details?id=bearface.games.merchant&hl=en
Copy the URL and post it into this website: APKPURE - this will down the direct APK to your computer. https://apkpure.com/
Attach the phone to your computer, drag the APK file into your main phone section (not the SD card), and put it into the APK folder.
Download this app to your phone - ES File Explorer File Manager
Open ES File Explorer - go to the APK folder, and click on the Merchant APK to update.
I thought non idling sucked too so i wrote this.
You need rooted android and hiro_macro (the root is for the app).
Within the :quest loop you'll see the logic that controls where the hero's go... at the top you'll notice i declare the x and y for the couple of areas within each zone... 1 is resource 2 is golem, etc. When using this you should make sure the quest map is scrolled all the way down.
find the "heros" variable and set that to the number of people you have. it doesn't work wil more than 5 ( and only tested on 4 ).
You can only go to the first four areas in a zone right now.
This will run your heroes on quests until they die, revive them, and keep running them.
Eventually i'll have it be a bit smarter and let you say "hero 1 can go here or here or here" etc. but for now it's a good way to burn all your gold getting resources and XP.
Also it's not my fault if you accidentally a rogue when by using this.
Oh I just discoverd I made a mistake. That wasn't Google Play Services which updated, but Google Play Games app. This one . Might be a step forward ....
I tried also clearing cache off GP Store, Games and Services but nothing worked.
I only started this game a week ago, and I'm having a blast. I found it through the Curated app. I'm happy to know development is still on going, and I wish you all luck on the Steam version which I will be following closely!
I just tested Helium, and it works as long as you are copying over data for the same version.
If you're not rooted there's a few extra steps to follow in the app description needed to work, but basically just download, install, and connect phone to pc.