how bad of shape is the piston/sleeve in? there are a few companies that will re-pinch the piston sleeve its not quite as good as a new engine but will get you rolling again inexpensively, just remember you will have to re-break it in. rayaracing has been recommended to me multiple times for their re-pinch service and its right around 25$.
i dont know of any company that will straight up swap you, i know Traxxas has an engine replacement deal but thats still around 110$.
there is the option of swapping to a SH.18, can find those new on ebay for around 60-70$, or even an upgrade to a dynamite .19 mach 2 for 110$.
could also attempt to sell and buy an electric.