InfoUSA.com has the most thorough and reliable database of consumer information available. You can drill in further by segmenting demographic, psychographic and geographic variables. Always use any purchased lists with caution to make sure you adhere to the Do Not Call list. Further informatio...
Apple specifically precludes anything that can't be delivered via the app from using in-app purchases. So you're free to tie a credit-card to services and real-world fees (think Uber) without paying Apple any transaction fees. Here's Apple's documentation on what they support (and don't allow) ...
You could easily do this via MailChimp or Klaviyo. More info: Klaviyo: https://help.klaviyo.com/hc/en-us/articles/115005255808-Integrate-with-WooCommerce#install-the-klaviyo-woocommerce-plugin Mailchimp: https://mailchimp.com/integrations/woocommerce/
My best guess is that you'd get it close to wholesale price, which is anywhere between 30% and 50% off retail price in the electronics industry. You'll need a sales tax license number to prove you're a business rather than an individual. Pricing requirements will depend on the manufacturer. S...
https://www.fraingroup.com - likely good place to start. Also setup Google Alerts to scrape Craigslist + email you immediately when something shows up you're looking for.
You can do this by using a server backend such as Parse. They have a free SDK. There are other similar options and I believe apple is rolling out the same thing in iOS 8 with CloudKit.