I see you are new here, like me. I am a Property Manager and Licensed Realtor in the Seattle/Tacoma area of Washington State. I have owned my own rentals for 30+ years. Not sure where your property is located so it will be real hard to give you any solid advice ...but maybe this will help:
1. Q.... what to charge?
A. Simply research your area via websites like rent.com or realtor.com etc and see what others in your area are charging. Drop your price a tiny bit below market and you will also keep your renters longer with less fuss with move-outs etc in general.
2. Q...do it yourself or pay a professional company?
A. If you have the time, resources, ability and thick skin... do it yourself and save about 10% in fees. Make sure you have good insurance and insist that your renters have "Renters Insurance". Professionals are like in any other industry, you must interview them and go with your gut feeling, after calling the BBB etc.
3. Q... either way you want to rent your home, so advertise it yourself or hire an Agent?
A. Either way is ok, again depending on your abilities and how strong you are. My wife tells me that I am a softie and give in to renters too easily without proper background checks sometimes. Yep, it happens. A professional will probably check people out carefully and be more strict in general if its not in your nature.
4. Q.... downsides?
A. Oh yes. ----- the downsides of renting is generally that renters can sometimes cause a lot of damage and not move out when expected, sometimes forcing an eviction and lost time which is money. In 30 years of renting our properties we have had several bad tenants, one kicked holes in the walls and stole all of our appliances and another caught the place on fire which resulted in our insurance paying $40,000 in damages.... BUT, that being said renting is probably one of the best things you can do if you are strict and stick to your guns. Do not play with it or be emotional, its just business. You can wait out the bad times when the market is against sellers, and your property will probably grow in Equity in most cases while the tenant pays the mortgage payment. Personally, I hire a professional Eviction Service now rather than do my own evictions and we are stricter now than years ago too. As time goes by rents go up, but your mortgage stays the same. (tell me you DON'T have an ARM...) :)
In any case, good luck. You can do it.
-Don Leske II / Associate Broker & Realtor
Here in Mass you have a few options. First, if you have an agency you like, you can sign an "Exclusive Right to Lease" form with one of them and your home will get listed on MLS. Of course, the Cape has a different MLS database than the rest of the state, and since you're in a desirable short-term rental location you want to make sure you're marketed to a wide range of consumers. Second, and more popular, is you can post your listing on craigslist. Most postings are free and you can upload descriptions and pictures. If you decide not to list with a single firm I would suggest calling every office in town and allowing them to market the rental for you. You are only responsible for paying the company that finds you a tenant. You can also try to get the tenant to pay a portion or all of the rental fee depending on how you price your home.