Dear Sir,
I have read your Project Description & we surely have expertise in front-end/back-end, iOS & Android App, as we have 50+ developers in house, few designers & some other staff. So, please go ahead and send me more detailed requirements, some reference/example website URL or can you drop me a message thru' Freelancer PMB to discuss requirements?
However, if you want all above, i.e. Front-end, back-end, iOS & Android App, then US $3,000 is surely very low budget.
Just so you know, our current bid is not our actual bid but just a placeholder to submit the proposal & start our communication.
Look forward to hearing from you.
Regards,
YK
LEADconcept