Greetings sir,
I have read your project requirements, and they are rather limiting in attempt to make a proper assessment. Our bid is based on some previous work experience with online stores, and while it has breached your budged limit, I strongly recommend, if you attempt to run a serious online store to think carefully how you'll get it running. We've spent far too many hours fixing other people's coding. :)
Now to the task at hand. The bid is defined by features you require on the store, as well as design elements that are needed. Needless to say, less features, more design elements you provide the lower the bid is and the time frame needed for us to make it. There are very few limits to what we can do, budget and time being the only true limiters. Usual features of online stores are payments online, shopping carts, database connections, login features etc..
Free Demos are our good practice, and we can offer one as to display quality of our work, and should you find it satisfying we can proceed with our work.
As for our expertise, we are team of 15 European PHP experts /Web / iOS / Android developers, all experienced in their field of work. Quality is our main goal, for the purpose of being team of choice for our employers should they need any IT work done again.
If you have any questions please do not hesitate to contact us.