Honestly, since you’re the buyer, there’s no real reason not to use a realtor (because they’ll take their money from the seller, not you). I’d just be sure to get one who knows their stuff (i.e. – make sure they have some level of experience dealing with vacant land, as it’s a whole different animal than what most realtors are used to dealing with).
Land Requires Different Sales Techniques – A home has a kitchen, bathrooms and a façade that can be visual and photogenic. You can hold an Open House for a home and walk a buyer through each room to help make the sale. Buyers can easily visualize themselves in – and fall in love with – the built home. It’s just not the same for vacant residential lots and land.