I don't have any firsthand experience with this, but I would recommend buying something on the cheaper end to start, so that you can see whether the item actually arrives and if it's in the stated condition before getting anything pricier.
The thing I would be concerned about is the payment method. If this place is not on the up-and-up, they might try to steal your credit card information. I'm not sure, but using a payment system like PayPal might protect you here. PayPal might also have a buyer protection feature, so if the item does not arrive or is not as promised, PayPal could take the money back from the merchant and refund you.
If the Instagrammer wants the sale done privately, without any option of buying through a third-party site (such as eBay or Poshmark) or the option of using a third-party pay system (such as PayPal), I would be extremely wary, especially if the prices are super low. Are the prices good, or are they *too good*?
If you decide to go ahead with a purchase, you could possibly use a *gift card* from Visa or Mastercard to make the purchase. That way the person wouldn't have your true credit card information. But they would still have your name and address, which would make me uncomfortable.
