I am not sure how to markup accepted payment methods for an offer.
Here are the Schema.org types:
Here is my basic example, is this correct?
<div itemscope="" itemtype="http://schema.org/Product">
<span itemprop="name">Product Name</span>
<span itemprop="description">Product Description</span>
<div itemprop="offers" itemscope="" itemtype="http://schema.org/Offer">
<span itemprop="price">$19.95</span>
<meta itemprop="priceCurrency" content="USD" />
<meta itemprop="availability" content="in_stock" />
<a href="/buy-now" itemprop="url">Buy Now</a>
<meta itemprop="acceptedPaymentMethod" content="http://purl.org/goodrelations/v1#PayPal" />
<meta itemprop="acceptedPaymentMethod" content=" http://purl.org/goodrelations/v1#PaymentMethodCreditCard" />
</div>
</div>