Build an Online Store

Note: The budget is tight so read the budget and apply for it. I am looking to build website for local grocery delivery. I know there are lot of templates out there in market and some sites like shopify/zepo already provide easy development option. However I would not like to pay monthly charges to these site. I would also like to build a macro or a code to copy data from other sites (e.g. big [login to view URL]) and upload the same on my site.