By purchasing a HQ downloads pack you obtain the ability word cloud images in high quality (HQ) PNG and vector EPS or SVG formats which can be used commercially without attribution to Tagul.com. All other features (fonts, shapes, etc.) are the same in paid and free accounts.
No you can't. If you wish to use a word cloud image commercially you will need to purchase one of the HQ download packs and download the image in HQ format.
PayPal is known to block some transactions but here is what you can do:
Yes, you can resell the images to your clients downloaded in HQ format. You can't resell SQ images.
You can sell the images downloaded in HQ under any pricing plan on stock image sites. But you can't sell free SQ images.