What is the best alternative to Megaphone - Voice Amplifier on iPhone?

Mic to Speaker - Virtual Mic, S tier, #1 in microphone to speaker.

Is there a free alternative to Megaphone - Voice Amplifier?

Yes: Mic to Speaker - Virtual Mic (S tier, #1) is free to download, with in-app purchases.

Yes. 3 apps rank above it in microphone to speaker: Mic to Speaker - Virtual Mic (#1), Microphone Live (#2), S1 & S2 Speaker Controller (#3).

Megaphone - Voice Amplifier is D tier, #4 of 6 in microphone to speaker. Here is everything that competes with it on iPhone, in tier order.

1
Mic to Speaker - Virtual MicShigher tier
Free + IAP · ★ 4.5 · 3,416 ratings · score 86
Routes an iPhone or iPad microphone to a connected speaker, with optional effects, automatic recording, and export.
2
Microphone LiveAhigher tier
Free + IAP · ★ 4.4 · 5,160 ratings · score 83
Turns an iPhone or iPad into a live microphone with low-latency audio, sound controls, and wireless audio output.
3
S1 & S2 Speaker ControllerAhigher tier
Free + IAP · ★ 4.4 · 12,317 ratings · score 81
Streams music from your phone library to a speaker over Wi-Fi or Bluetooth, and broadcasts live microphone input and.
5
Live Voice Changer - PrankcallF
Free + IAP · ★ 4.4 · 4,741 ratings · score 45
Changes your voice in real time through the iPhone microphone, with voice presets, reverb effects and a recorder.
6
Megaphone FREE!!F
Free · ★ 2.6 · 4,658 ratings · score 27
Records and amplifies your voice, and lets you send the louder sounds to friends by email.

What is the best alternative to Megaphone - Voice Amplifier on iPhone?: Mic to Speaker - Virtual Mic, S tier, #1 in microphone to speaker.
Is there a free alternative to Megaphone - Voice Amplifier?: Yes: Mic to Speaker - Virtual Mic (S tier, #1) is free to download, with in-app purchases.
Does anything rank above Megaphone - Voice Amplifier?: Yes. 3 apps rank above it in microphone to speaker: Mic to Speaker - Virtual Mic (#1), Microphone Live (#2), S1 & S2 Speaker Controller (#3).