The main pro of a cheap toaster is that it costs the buyer less money than a mid-priced or expensive model. A major con of choosing the cheapest toaster may be that it doesn't toast bread evenly and/or it won't last as long as other models. If a toaster is cheap because it's on sale but is actually a good model, this can be a big pro.
The easiest way to tell whether a low-priced toaster is actually a higher priced one on sale is to get a price history. It's best to check the price for the toaster at different stores to see how they compare. Checking different stores' appliance departments regularly is also a good way to find quality toasters on sale for what a cheap one would cost. If a cheap toaster is always basically sold for about the same price and also doesn't have a warranty, or it has a very limited one, it's probably more of a con than a pro as far as value is concerned.
If a toaster is rarely used, such as one in a seasonal cottage or vacation home, a cheap one may be a pro. Leaving an expensive toaster to just sit without being used can seem like a waste of money. If an inexpensive toaster becomes stolen or damaged, it isn't much of a loss expense-wise. If there is another method for making toast such as using the oven, then a cheap toaster's breakdown becomes even less of a con.
When looked at over time though, having a cheap toaster can seem more like a con if it is always breaking down and needing to be replaced. A good-quality toaster that will last many years with more reliable service is usually preferable to a cheap model for most people. Also, a cheap model may not work as well as mid-priced or better toasters, so this can be a strong con.
When many items for a kitchen or a home have to be purchased at once on a tight budget, this is when a cheap toaster can be a pro. The money difference between a cheap model and a more high end toaster could then be used to buy other necessities such as dishware or cookware. If the budget isn't extremely limited though, a cheap-quality toaster is more of a con since the money may be better spent on a better model that will last longer.