A couple takes a selfie as they stand next to a heart-shaped paper flower decoration at flower market on Valentine's Day in Islamabad, Pakistan, Feb. 14, 2016. REUTERS/Faisal Mahmood

Tuesday is Valentine's Day, and if that's news to you, you may be in trouble. Women and men in romantic relationships expect gifts of some sort for the love-themed holiday, meaning you probably should have bought a present weeks ago for your special someone.

Americans will spend about $18.2 billion celebrating Valentine's Day this year, a number that averages out to about $136.57 per person, according to the National Retail Federation. People spend about $85 on their significant others, about $27 on relatives, about $7 on kids' teachers and/or classmates, about $4 on coworkers and $4 on pets.

If you haven't gone to the store yet, don't panic. You still have time to get — or make — a valentine and avoid a breakup. These ideas are organized by "for him" and "for her," but remember you can get anyone anything. It's the thought that counts, after all.

For Him

If your boyfriend is an audiophile with a long commute, you can't go wrong with a pair of headphones. NYMag suggests buying these $489 Professional Open-Back Reference Headphones, but you can get blue EP On-Ear Beats from the Apple store for $99.95 or these $49.99 INK'D Wireless In-Ear Headphones from Skullcandy.

Does your man have — or want — a beard? AskMen suggests signing him up for the Dollar Shave Club, a service that sends subscribers a razor for a one-month trial for $1 and subsequent cartridges for cheap. Your SO can even adjust the frequency of deliveries if he doesn't shave often.

Whether he's a casual fan or proud geek, your hubby would probably love some "Star Wars" gear, according to Time. Score a vintage "Star Wars" movie poster on AllPosters for $113.99 or a First Order Transporter Lego set for $69.99 at Target. May the force be with you.

For Her

This may seem like a fallback, but who doesn't love a fresh bouquet of colorful flowers? Find and call your local florist using this website, then send your loved one red roses. If she's not a roses type of girl, check out Edible Arrangements' $119 Be Mine Bouquet — it's full of strawberries, grapes, chocolates and pineapple. Yum.

Bath bombs are all the rage both in the tub and on Instagram right now. Head to your nearest LUSH store to pick up an Intergalactic, which promises "out-of-this-world baths," for $7.75. If you're feeling creative, you could instead make a bath bomb of your own using these instructions from BrightNest. Tie a ribbon around it when you're finished, and voila! It's a gift.

There's nothing better than curling up in bed after a long day with a book. BGR suggests you take this tradition into the 21st century with a Kindle. Go on Amazon to see which model would best suit your lady's needs — the standard affordable Kindle for $59.99, the screen-glare-less Paperwhite for $99.99 or the super-thin Oasis for $289.99.