Tech co-founder 2-3 startups like Ravox.com and SocialDefender.com, strong in social commerce, scalable platforms. Founder of web development agency. If you have questions about dev stack selection, technical architecture, scalability, web app performance call me
There are indeed a number of off the shelf frameworks for the web platform and mobile apps. You should find a few by spending some time. First, identify a mainstream app that's close enough for your concepts like TaskRabbit or dolly or uber. When you are looking for it look for xxx clone script. Make sure the platform is available with source code. Many cases they can fit the platform to your requirement without starting from scratch. That would save around 80% of the development. It might be worth looking for a platform other than WordPress to create scalable platforms.
I own a mobile app develop agency for the last 15 years. Few other requested apps like opentable before.
To create the main functionality of opentable - web app, mobile app, main management panel, restaurant app) from scratch it would take around 2500-3000 ours of coding. this is based on estimate one year back and assuming you are starting from scratch.
If you were to customize existing platforms like iScripts UberforX it would be closer to 500-750 hours.
I run a mobile development agency for the last 15 years. So I am a little skewed.
Before you start looking for somebody to get the app developed, start with very detailed specs. The more detailed it is the better. After that start creating the user flow. There are tools like invisionapp.com to create good app screen mockups. another decision that would impact is going going to be which platforms you want to create the app, native is, native Android or both or or a hybrid app like react native. In your case, a hybrid solution might be better if you want the app to support iPhones and Android users.
You get some high level estimate using some tools like https://www.app-estimator.armia.com/ . this would help to get an idea what to expect when you talk to developers. Get few proposals from freelancers and agencies.
Good luck with your app
I am assuming this is a genuine question.
I will be blunt. A ticket in the powerball lottery have a potential to return $500 Million. But the ticket price is at $1 due to the low probability irrespective of the potential. Similarly the probability of seed funding company provide decent return is 5% and the probability of it provides some return is another 5%. 90% of the seed investments lose. There was a paper from David Rose with the accurate numbers from gust platform.
Typically investors take 10-20% in each round of funding.