Standard or Ultimate: what changes
Separate the base game, the upgrade and the preorder offer.
GTA VI has two announced editions: Standard and Ultimate. Standard includes the game. Ultimate adds a bundle of in-game extras, and Standard owners can buy the Ultimate upgrade separately. That makes the important buying question the value of those extras, rather than a fear that choosing Standard closes off the upgrade later. See Rockstar's edition FAQ.
Compare the right prices
The US PlayStation page lists US$79.99 for Standard and US$99.99 for Ultimate at the time checked. Those are regional digital-store prices, not a promise about every country, retailer or tax treatment. Check your own account's storefront before comparing a retailer's code with a digital purchase. The US edition selector identifies the product and currency.
Ultimate's extras include vehicles, weapons, styles and other in-game benefits. The detailed names and story-related reward descriptions are available with spoiler-free mode disabled. Neither edition's product description is an independent assessment of the value of those items in actual play.
Preorder benefits are a separate offer
The Vintage Vice City Pack is a preorder promotion. Sony also describes a one-month GTA+ offer for eligible digital full-game preorders, with redemption terms and automatic renewal. Do not price that as a permanent subscription or assume that a retailer's boxed code carries an identical membership promotion. The full storefront conditions, including the claim deadline, matter more than a cropped “one month” badge.
You can upgrade after choosing Standard
Rockstar says the Ultimate upgrade can be purchased separately after the Standard code has been redeemed. The boxed Standard product therefore does not become an Ultimate box with a disc: it remains a download-code purchase plus a separate digital add-on. Read the boxed-copy guide if ownership format is the reason for buying at retail.
For a straightforward launch purchase, establish the platform, account region and edition first. Then compare the final cost of the exact product, including any membership terms you intend to accept.