Elaboration. Well firstly since you are interested in the colonial towns if you head north from the Michoacan beach towards the Costalegre hang a right off of Highway 200 at Tecoman and head up to Colima and Comala for the night, it's only 25 minutes up the 4 land highway from Tecoman. Apart from the museos and the two sets of ruins, La Campana and El Chanal, you can drive up past Comala to get a good look at the active Volacan de Fuego. Some places I know personally that are nice to stay with parking are, Hotel Ceballos or the Merced in Colima's colonial centro or Casa Alvarada B&B in Comala.
Then you can head back down to the coast either the way you came or on the old Minatitlan highway. If you take the old road stop off at the El Salto waterfall, just past Minatitlan, to cool off.
The Costalegre is very natural and undeveloped compared to places like Puerto Vallarta, Ixtapa, Los Cabos. We don't have malls, chain grocery stores or fast food outlets -- those are in Manzanillo 65 km away. We do however have 5 very good resorts, most would be priced over your $200 USD limit but they do run web-specials from time to time so if you are interested check them out on line. They are Grand Bay Isla Navidad, the only one that is really close to a town being across a sea channel from Barra. The others are off of highway 200 and not situated very near any real towns. Heading North from Barra you will find, El Tamarindo, El Careyes, Las Alamandas and El Hotelito Desconocido.
If your tase runs more to a town to stay in there is a good and varied selection of accommodation available in Barra de Navidad and Melaque located on Bahia de Navidad. This is a good place to use as a base to explore the southern part of teh Costalegre. Both towns have good selection of restaurants and fairly quiet beach bars. The 4 storey Alondra hotel in Barra across the street from the beach has a nice roof deck bar where you can watch the sun go down. I prefer Barra to Melaque -- but I have lived in Barra for 8 years so my opinion is not unbiased.
Heading north the next little town La Manzanilla is on the beach of Bahia Tenacatita. It is a quaint little fishing village with three little budget hotels and a pretty good selection of other more upscale accommodation either in homes, bungalows or guest houses.
The next place also on Tenacatita Bay is Tenacatita. They have miles of golden sand beach with gently breaking waves and a coral reef for snorkelling but there is no real town. It consists of 3 or 4 motels, several restaurants and a little hotel. There is not much to do there at night but watch the waves break on the beach in the moonlight.
The next "villages" with accommodations at the beach are Chamela and Perula located on Bahia Chamela. Perula is more of a little town than Chamela which is really only a couple of motel style hotels at the beach. Perula has little stores and several restaurants on the beach but both are quite rustic. The beach on Chamela Bay is very nice and there are some islands in the bay, one is a bird sanctuary, that you can visit by boat. There is pretty good snorkelling off those islands as well.
Then, if you are really into exploring "off the beaten path" you can venture into tiny little Tehuamixtle on Cabo Corrientes. There is a pretty good sand and gravel road in from Cruz de Loretto and a the same out to El Tuito. There is a hotel with pool on the beach at Mayto about 5 km away and both Gabby at Candeleria's restaurant and Lorina at her restaurant across the street right in Tehua rent simple but clean beachside rooms.
Hope this helps you decide.