Add product options without variations in WooCommerce
Colours, sizes, finishes and add-ons on one product, with no variations behind it. Four steps, free.

Set it up
You need AddOnBoss, free from WordPress.org.
Go to BossMage, then Option sets, and press + New set. Under What kind of set?, press or use a template on the List of choices card and pick Finishes.
Nothing close? Press Start blank and type your own choices.

Name the set. Under Adds, type what a choice costs on top of the product, then press Save set.
Here Gloss adds £4 and the laminated finishes £3. Leave 0.00 where a choice costs the same. Edit details adds a colour, a photo or a note. The Customer page beside the editor shows the set as shoppers will see it.

Edit the product, open the Product options tab, open Attach an option set and pick your set.
Type to find it. On its row, choose Optional or Required.

Press Update. The choices are on the product page with a live total, and no variations were made.
Common questions
Why not just use WooCommerce variations?
Variations multiply fast. Five colours by six sizes is 30 variations, and a third attribute takes you into the hundreds, slow to load and painful to manage. Options give the same choices with none.
Can I reuse a set on other products?
Yes. Attach the same set to as many products as you like. Edit it once and every product that uses it follows. A choice already in a cart keeps the price it was added with.
Can a customer pick more than one choice?
Yes. Under Picking, switch from One to Several. Each pick adds its own charge, and At least and Up to set a limit if you need one.
Is this free?
Yes. Option sets, colour swatches, per-choice prices and show and hide rules are in the free AddOnBoss plugin. Photos on choices, stock on a single choice, file uploads, rules on numbers and per-letter pricing are Pro.
Every setting: option sets documentation. Or show a question only when it applies: conditional logic guide.