One of the avionics suppliers has put together an IFR “lite” panel. It’s still $30k, and I would add a G5 back up as well.
Not sure you can do IFR cheaply.
This is pretty close to my setup, capability-wise, except instead of the GTN650 I have a GNX375 plus a backup G5. It was about $30K.
When I consider "lite-IFR" it's more about being in a single-engine airplane that whatever capability I have on the panel. We spend a lot of time in primary flight instruction in forced landing scenarios. As a CFI, I generally teach this maneuver starting about 3,000' AGL, and once a pilot gets the hang of it, I expect them to be able to get to an acceptable solution at almost any point in the flight. But even at 3,000 ft, I often have to steer the flight to somewhere that offers sufficient choices of emergency landing fields.
Now, let's consider the 'lite-IFR" scenario. When we think about IMC ceilings, 1,000 ft overcast is generous to make an instrument approach. But what if you have an engine failure at 8,000 ft cruising altitude and you descend IMC at Vy, pop out of the clouds at 1,000 ft, and now you have to find a field and land on it. To successfully complete this maneuver from 1,000 where you first have visual contact with the ground, you must first be lucky, as your gliding range at 1,000' is pretty small. Secondly, you must be very proficient at emergency landings to have a successful outcome.
How low of a ceiling are you willing to fly in a SE airplane in lite-IFR? Whatever your answer is, go out and fly at that altitude, and simulate and engine failure and see what your options are and how well you could land from there. Be honest with yourself and see how much of the time there are acceptable fields within gliding distance and how often there aren't. Then reconsider what you mean by "lite-IFR."
When I was young and dumb, I flew a Grumman Yankee in IFR on round dials, VOR, ILS, and NDB. I didn't have an autopilot and due to the fuel being inside the wing spar, I could rarely take my hand off the yoke because there wasn't roll trim, and it was almost always out of balance in roll. I never considered a forced landing while IMC and it was only by dumb luck and the grace of God that I survived my own poor decision making.
I’m currently not instrument rated and don’t really have a desire to obtain the rating, but I’ve been contemplating getting it as I would plan to recreationally travel and fly X/C’s if I owned an RV. If I were going to build a Vans (7-9) or bought one with a VFR panel and wished to update, which avionics would be the least expensive while still qualifying for flight in IMC? I don’t plan to do hardcore IFR flight, I’m simply considering the rating to avoid being stranded at a distant airport or worse, stranded in the air due to sudden IMC conditions popping up. So I don’t need a super fancy glass cockpit with dual screens, etc.
I’m painfully aware that the words “inexpensive” and “avionics” do not mix, and even the least expensive panel will probably chew a minimum of a $20k hole in my wallet. I just don’t want to spend $100k on an instrument panel. I’m also aware that if I buy used, it’s far easier/more affordable to go ahead and buy an RV that is already equipped with IFR. I’m asking primarily in case I build. And I may choose not to obtain the rating, but am exploring options just in case.
I'd caution you to honestly evaluate how much risk you are considering with this approach. IFR capability is only as good as your own proficiency. Continued VFR flight into IMC is one of the leading causes of aviation accidents and fatalities. You either have to commit to being an IFR pilot, and constantly train to it, or limit yourself to VMC flying. Do one or the other, because having an IFR rated airplane and a VFR proficient pilot is a bad combination. Accident reports are filled with dead pilots and dead loved ones of pilots who didn't hone their craft and had to get somewhere right then. As they say, when you crash on a bad weather day, it will be a sunny day when you are buried.