Hello!
I have recently built the LAV-25 from Trumpeter and that thing was really pleasant to build. The fit was really nice. There are some fiddly suspension bits at the bottom but they are manageable. It was $26 on Amazon.
If you are pretty confident in your skills and want to dive off the deep end and get something I would say get the Zvezda T90, its $32 on Amazon and is really detailed and the fit of the parts is really good, it just requires some finer sanding and such.
If you like American stuff, theres a Cyber Hobby M1A1 kit for $30 on Amazon as well, and I hear thats pretty good.
Honestly, just buy whatever suits your fancy around the $25-$35 price point.