We use Adobe Stock for photos as well as clipart. It seems reasonably priced and has a decent selection of images. There may be limits on the number of impressions you can print with a particular license. But I never even come close to the limit. I can even upload an image into a search window and I can then download the full rez image from their stock if they have the same picture, which they often do. They also have watermarked comps that they call "previews" that can be used for free for customer approval before I buy. I can also send the Adobe Stock link to my customer to peruse on their own time and not tie up my computer or a salesperson's time. They then just give me the stock numbers for their choices.
There may be advantages to using some of the other image-licensing services (larger choice of resolutions, for instance). And restrictions are similar to those on other services. Clipart cannot be part of a logo design or branding scheme, for example, since all the copyrights to the images are owned by the original creators. Adobe Stock is just a middleman. The US Patent & Trademark Office will always deny registration for a trademark that incorporates clipart. But this restriction is a standard proviso with all the image-licensing services, which makes sense. Clipart has no place in a "logo" design, anyway, since it can't be protected, in addition to being copyright infringement.
Add the subscription cost to your monthly overhead. We don't charge a separate fee for an image unless we have to pay a separate fee for an image from another site (like Getty!).
Brad
cold in Kansas City