What Extender to purchase

A few questions. 

1. what actual router do you have? Most AC1000 routers aren't even gigabit. And AC1000 is a speed, not a model
2. what speeds do you pay for? 
3. what speeds are you getting in the master suite? 
4. What is your goal for speeds in the master suite? 
5. Whats your budget? 

These are all important questions. While range extenders do add range, its at the cost of speed. This happens because they drop throughput 50% of what they receive. This happens because they have to use the same chip to go router----extender and then extender----device. And they can't do both at once. So determining what speeds you're getting out of what exact router are key. You might be better to upgrade routers versus adding an extender. But tough to know without all the details. 

Sorry....Old guy Newbie....Model R6080     The real issue is my iphone (not computer) jumps from "wifi" to 5g  when I'm in the master suite. I was told an Extender would correct that. Computer speed test in office where router is 94.6 Mbps (Down) and 14.4 (up) and back in the master suite it is 36 Mbps (Down) and 7.3 (up). My goal is to have my phone stay on "wifi". The budget is "what it takes to correct the situation without over spending"..... Fixed income retired guy. Thanks.

Almost any WiFi Extender would probably work.  I have been most successful with TP-Link and Netgear WiFi extenders.

TP-Link RE315 sells for under $25 on Amazon.  (Overall Pick on Amazon).  If it doesn't work, you are not out much.

Be aware that WiFi extenders keep devices on the same local IP subnet as the primary router network, but mobile devices may not roam seamlessly between the primary WiFi system and the WiFi extender (even if they both have the same - identical - WiFi SSID & password).  Thus, it may be necessary to "turn WiFi off and back on" to get the iPhone to switch from one to the other.  This is the reason mesh WiFi networks were created a decade ago.

As cheap as those extenders are, I think you'd be better off to invest slightly more. That R6080 is old/slow and could be part of your bottleneck as it isn't even gigabit. You're hitting 94 Mbps so its indicating your speed is bottlenecking there. If you're ISP is giving you 300mbps, but the router is limiting it to 100, you're starting at a lower point. 

If it was me and I was on a limited budget? I'd check your local facebook for a used orbi setup. I"d look for the 20 through 50 series (avoid the 10). They can be picked up pretty cheap used, would give you a gigabit router and then a satellite with a dedicated backhaul. I've seen them used in my area (Minneapolis) for that $25-60 depending on the series. It costs a little more and they're used, but you'll get better performance than a single/dual band extender. Plus you'll upgrade the router and have a higher starting point. 

Again, that's just me. 

plemans​ has a valid point. Used WiFi5 systems are not all that expensive.   Amazon sells WiFi6 in a  "2 pack" for about $100.

It is also worth asking what speed the ISP is providing.  If they claim to supply over 100Mbps (even 1mbps over 100), then the Ethernet cable linking the R6080 to the ISP device (modem? DSL?) may be restricting the maximum speed.