To buy or not to buy, that is the question. Travel insurance is an interesting product that I can debate for hours. Some are sold and never travel without it, while others think its a waste of your hard earned money.
For anything more than an affordable sun holiday, I recommend you buy comprehensive travel insurance. Most comprehensive plans will not only cover emergency medical costs (which could be in the thousands) but they also provide baggage loss/delay coverage and more importantly trip cancellation coverage.
There are dozens of reasons why you may have to cancel a trip or cut a trip short (family emergency, travel operator goes bankrupt, layoff, etc).
Never buy your insurance from the broker, agent, company or website selling you the trip. Typically you can find better deals from larger third party agencies like American Express, BlueCross/ BlueShield, CAA/AAA, your bank, etc.
Shop around for the best price/coverage and read the fine print. Not all insurance is created equal. Some accept trip cancellation due to a layoff while others do not. Some provide a partial reimbursement for trips cut short due to family emergencies while others do not. Whatever you buy, make sure it has comprehensive health coverage with a dedicated 24x7 internationally accessible medical support line.