MontCaribe is the place for you if you're looking for clean, simple accommodation at a reasonable price ($50-60 night for studio w/ kitchenette) that's located within walking distance of the beach at Ocean Park (it's about 3 blocks away). The beaches in San Juan are divine; gorgeous aquamarine water, velvety soft sand, and whitecapped waves.
The hotel is also 1/2 block from Calle Loiza, which is a major strip with public transit, small shops, bars, and also larger stores such as Walgreen's. (Note that C. Loiza can be a bit dodgy after dark so plan accordingly). You can catch the bus there that goes to Old San Juan. It's about a 20 minute trip (once the bus comes, if you know what i'm saying) and the fare is 75 cents, exact change only.
A half block from the guest house on Calle McCleary, there's a fantastic little Burrito & Taco Bar with fun day of the dead type decor and reasonable prices. Next door to it is the always busy Kasalta Cafe/Bakery. You can continue on Calle McCleary all the way to the upscale Condado, where a number of the big hotels can be found, along with high end boutique shopping -- if that's your thing.
The rooms / suites at MontCaribe are furnished with a comfortable bed, table and chairs, color cable TV, kitchenette with fridge, stove, and microwave and a bathroom with shower and plenty of hot water. The kitchen had odds and ends in it such as 2 bowls, 1 plate, 2 glasses, a few utensils and a pot for boiling water so I went to the dollar store at the corner and picked up a mug for 99 cents and bag of plastic spoons and I was good to go.
There's supposed to be wi-fi in all the rooms but we couldn't get the signal to reach to my studio, even though the staff helped me by testing a different router. Instead I did my email from the courtyard area in the morning and inside the office area in the evening. The professional and fun Kymberly at the front desk is perfectly bilingual and always willing to help with information re directions, transportation, and activities in the area.
As a solo female traveler I felt safe at MontCaribe as there's good security with a gated entrance and a clerk at the desk from approximately 8 am to 8 pm. After hours there's the cute yet vigiliant Chammo, the resident dog that is friendly toward guests but also does his job being protective of the premises if need be.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC