Sorry for the delay in replying, took a couple of days off. There just too many messages in my inbox, I am not able to get through all. This is what I will do, I will accept the first article for $2. If its up to my expectation I can pay $3-$5 for the 20-50 articles. No upfront payment, prefer to pay once by paypal because of the charges. Thanks!
For all of them, really? Or per article? The sellers (writers) incur the PayPal fees, not you - so this is no excuse not to offer upfront payment.
I don't know any professional or freelance writers that would accept payment upon completion. First of all, the writer will take all fees, so your reason for no upfront payments is bogus. Second, who is to say you wouldn't simply take the articles and never pay? This is why when we do not work side by side in an office with the client, we ALWAYS do a percentage of payment upfront. That ensures that not only we will complete the project for the rest of the money, but the buyer is SERIOUS and intends to pay the rest when the project is finished. And last but not least, even at your top price of $5 for a 500 word article is still ONLY $1 per 100 words. That is an EXTREMELY cheap rate, and not many high quality writers will take that project on. It takes us time and energy and all of that is worth way more than 1 cent per word.