I went to the White Suites in Playa Blanca Lanzarote by myself last November and I think you'd get a week's B&B for that price in winter, although HB was only £4 a night extra when I booked. It had 2 pools, one heated and a jacuzzi and a small spa which I didn't go in.
Dinner was a buffet, which I'm not a fan of, it was fine but a bit bland. However as I prefer to get a nice lunch mid afternoon while out and about I figured that I wouldn't want much but probably 'something' in the evenings, so I'd get a bit of salad and a glass of wine while I sat in the restaurant for a while in the evenings.
There's loads of cheap flights there in the winter and I just got the normal bus from the airport to PB bus station which is about 15 minutes walk from the hotel. The seafront is about 5 minutes walk away and then you can walk for miles in each direction, there's a regular bus that goes end to end as PB extends several miles along the coast. As well as swimming in the sea every day and going for walks, I went on a coach trip to see a few gardens, houses, viewpoints and caves associated with the local artist Cesar Manrique.
Join the H10 club for extra discounts and if you can stretch to it, get a pool view room as my balcony faced the road, so was a bit noisy, wasn't a huge problem but I like to sit on the balcony so a quieter room would have been nicer. If it came to it, I'd rather have 6 nights in a quieter room than a week in a 'road view' one.