Pastel

Mugi Tadano is a 16-year-old boy who lives alone; his mother died years ago and his father is always on frequent trips as a photographer. When his first girlfriend, Hinako, leaves him for Tokyo, he is understandably heartbroken. Kazuki, Mugi's best friend, invites him to work with him at his aunt's beach-side inn, in the hope of helping him shake off his depression.

But things take a fateful turn one day when, while at work, he spies on a beautiful girl, Yuu Tsukisaki, changing clothes in an alley behind the inn. Yuu, instead of getting angry, charges him ¥120 (approx. $1.05 USD) for watching her. This isn't the last that he would hear from her...

The manga has been running since November 2002 and is ongoing in Magazine Special, having spanned over 25 volumes. There is no anime adaptation as of yet.

Tropes used in Pastel include:

Accidental Pervert: Mugi, full stop.
Annoying Younger Sibling: Tsukasa half the time. The other half she's a well-meaning but bumbling Shipper on Deck.
Beach Episode: Complete with Slippery Swimsuit moments.
Big Friendly Dog: Mametarou
Bitch in Sheep's Clothing: Kiku Murikami, who doesn't appreciate Mugi refusing her advances and sets out to destroy Yuu's reputation.
Cannot Spit It Out: ...only sometimes.
Cute Kitten: Mikan. Complete with "found abandoned on the roadside in a cardboard fruitbox. In the rain."
Handsome Lech: Kazuki's exotic looks and cheerful personality make him the target of admiration amongst the rest of the school's girls. However, his 'lecherous' personality comes out full swing whenever one of them gets the courage to confess to him and it usually ends with an Armor-Piercing Slap.
- Justified in that he's been harboring a crush on Manami for the last decade or so, so he acts over the top to discourage said girls.
House Husband: Mugi is noted to be an excellent chef and has been maintaining the house since he was in 5th grade.
I Have Boobs - You Must Obey!: Seemingly invoked with Mako
Oblivious to Love: Mugi seems to be the target of numerous crushes from people he's randomly met/helped, yet never finds out until somebody explicitly mentions it to him.
Parental Abandonment: Mugi's mother passed away when he was young and his father is almost constantly away on photography trips. Yuu and Tsukasa comes to live with Mugi after her father dies and her mother remarries.
- Averted slightly because it was Yuu and Tsukasa who "abandoned" their mother, not wanting to give her trouble with her new stepchildren.
Scenery Porn: The series mostly takes place on the coast of Onomichi, Hiroshima. Some of the page spreads in the manga are absolutely gorgeous.
She Is Not My Girlfriend: Mugi and Yuu pass themselves off as distant relatives initially to avoid scandal in the Close-Knit Community. It's an excuse that seems to stick, much to his chagrin.
Shipper on Deck: Her sister, his dad, his best friend, his childhood friend, his ex-girlfriend...
Unresolved Sexual Tension: The image for this trope probably happens in a third of the chapters.